How did prog rock become the laughing stock...

All these theories sound plausible but on closer examination ...? 

One premise is that Prog was middle class because the musicians and their audience were middle class, and likewise Punk was working-class because the musicians and audience were working-class. The big problem with that is the youth-population of Britain didn't suddenly go from being mainly middle-class to mainly working class in between the end of 1975 and the middle of 1976. Which raises two related questions: what were the working-class listening to before Punk? and what where the middle-classes listening to after Prog? For there to have been a class-divide between the two genres of music would have meant that they could have (and should have) co-existed without one affecting the other. That the (disaffected/unemployed) working-classes suddenly developed a music of their own would have had no bearing on what middle-class college students listened to when toking on a spliff in their halls of residence or student digs. Prog and Punk appealed to young people of all classes. The only "class" that hated Punk were the middle-aged, middle-class middle-Englanders - (aka Mrs Mary Whitehouse and her ilk) and they hated all youth culture regardless of what it was (and still do). [NB: the notion of race here (i.e. white middle-class) is irrelevant - neither Prog nor Punk had much impact on the non-white community who were content with listening to Soul, Disco, R&B and Reggae music]

It is a similar situation for the musicians, though the evidence of a class-divide among musicians is less clear. While it seems superficially true that to achieve a level of musical proficiency to play Prog requires a formal musical education that in the 1970s could be presumed to be only available to the middle-classes, we know that very few Prog musicians had this level of musical background and most of them were self-taught. So there were certainly many working-class Prog musicians and several well documented cases of middle-class punk musicians - Joe Strummer was the son of a diplomat, the 'Bromley Contingent' came from the same middle-class area of suburban Greater London as Peter Frampton and David Bowie, the Stranglers came from Guildford (probably the most middle-class town in middle England's stock-broker belt). It is estimated that nearly half the Punk musicians were middle-class and a third of them had a university education - Punk as was much a product of Art School alumni as Prog ever was, if not more so... And that's a significant point - Punk was not just music - it was an art movement - the Sex Pistols were manufactured by two middle-class Art students with a "product" to sell; whereas Prog (unlike Psychedelia before it) was just music without a subculture and Art-background to support, promote and maintain it. 

Of course, therein lies the problem with Prog and why we find it so hard to define, classify, and compartmentalise. Whether through accident or intent, it lacked that cohesive common-ground to unify and define it - so it was easy to ridicule Prog because anything chosen to illustrate how pompous and overblown it was automatically became representative of the whole genre, even when in reality it wasn't. For example Genesis taking hampers of food on tour with them is used to show that they were aloof and middle-class, whereas the truth is they couldn't afford to feed themselves in restaurants and bars every night. I would suggest here (and this is just a theory) that Prog musicians distanced themselves from any form of subculture in direct reaction to the post-hippy come-down and the death of the Summer of Love - Prog was a leaderless anti-hippy freakdom of music devoid of all that non-music baggage whose only ethos was individuality and self-expression. If Punk ever honestly rebelled against anything, it was that - Anarchists in name only, Punk was actually conservative and conformist - to be a Punk meant adopting the whole shebang: the art, the music, the style and the uniform dress-code - right from the tippy toes of their Doc Marten boots that Mummy bought for them to their tooth-paste spiked hair and the "I, Individual" tattoo drawn in biro on their foreheads - One cannot be simultaneously left wing and libertarian, and there the whole class-divide comes crashing down because class and politics are only loosely aligned - bands such as Sham 69 had as many right-wing skinhead followers as they had left-wing, no-wing punk followers... On the political spectrum what came after Punk was ten years of Thatcher and Regan Conservatism, not in reaction to Punk but as a direct disaffected consequence of it - the people who voted for them were the same people who pogo'd and gobbed to Anarchy In The UK and God Save The Queen four years earlier.

The "classing-down" of Punk and its musicians was a media invention that snowballed because it sold newspapers and (eventually) records. In retrospect it made bigger "stars" of the music journalists who wrote it than most of the Punk musicians they wrote about. Middle-class Punk musicians latched on to this because it was a lucrative bandwagon to climb aboard - all free publicity is good publicity and when the music press is "on your side" then it would be daft to deny that it was true. 

Similarly, the myth that they couldn't play their instruments, a put-down that had historically been levelled at any emergent music trend by established 'professional' musicians (this had been said of all pop bands from the Beatles onwards and still persists today), was turned-around and used as a battle-cry with such conviction that the public believed it not only to be true, but believed it to be a prerequisite for making this "new wave" of music long after the evidence presented by post-punk and all that followed after has proven it to be false. To be a Punk meant conforming to the ideal regardless of how proficient the musician really was - flash solos and musical self-indulgences were frowned upon (by the music-media) and musicianship was suppressed (by the musicians themselves).

[And seriously, I couldn't give a flying fart what Johnny-come-lately Jello Biafra said or thought three or four years after Punk had officially curled-up its toes and died...]

Sorry, but I can't agree with that at all.  

I lived in the SF bay area and saw Jello and the Dead Kennedy's several times through the 80's and some historical perspective is necessary to appreciate what they were doing.  In the 80's, Jello's lyrics and the DK album artwork promoted an anti-Reagan political stance that was extremely relevant.  Many in the US felt that Reagan was just a couple of moments away from starting WWIII with Russia ("the evil empire") at his whim.  The DK's took that issue straight on...not to mention the hypocrisy of TV evangelists and our undeclared war in central America.  Also, the album artwork and 12" x 12" posters included in their albums (especially HR Gigers "Penis Envy" included in the DK's Frankenchrist album) put Jello at the forefront of the fight for freedom of expression and a direct target of lawsuits.  There were other US hardcore bands with similar political agenda's (The Minutemen, Millions of Dead Christians - aka MDC, etc) but Jello and the DK's were always the lead dog in the fight against Reagan conservatism...and as such the biggest targets.  

I myself like the Sex Pistols, Clash, etc. far more than ELP, who are dismal and horrible.  90% of Yes is also not in my cup of tea, despite their masterpieces.

And I listen primarily to prog - RIO, Avant, classic, kraut, etc.  

Musical tastes are not about technique, except for some musicians.  The context, message, etc. all matter a great deal in any artistic consumption.

Exactly.

People seem to think that Punk and Hip Hop and regular Rock songs are about the 'real world' while Prog is about the 'fantasy world'. So Prog is considered 'silly'. It's similar to how fantasy novels and sci-fi novels are not considered 'real literature'.

The same thing happens to Goth bands like Bauhaus and Sisters Of Mercy. People see the clothing of the band members and the song titles and immediately dismiss it without actually listening to the music carefully.

When I was a teenager, music magazines always dismissed bands like Led Zeppelin and King Crimson as bloated pretentious hippy fantasy music. So I never bothered listening to any of their albums. When I finally heard their music properly, I was amazed at how good it is.

Personally I don't trust any music critics at all, I've read so many reviews where it's obvious that they haven't listened to the music closely and they are just following the status quo of what other 'tastemakers' are saying.

At least half of the music I love to listen to is not 'approved' of by music critics or the general public.