It was avery good year

In prog we welcomed Meddle, Aqualung, Tarkus, Led Zeppelin IV, Every Good Boy Deserves Favour, and Yes managed to release two classics that year, The Yes Album and Fragile.

Moving away from prog (if only slightly in some cases) we got Whos Next, Surfs Up, Imagine, If I Could only Remember My Name by David Crosby, Teaser and the Firecat, What's Going On, LA Woman, Masters of Reality and the list goes on and on.

Has there been a better single year for the release of outstanding albums?

Me, too! (Do you have a wife/sister named Barbara?)

Buy I can add this reinforcement: your list doesn't even include one-tenth of the albums on my list for that year:

So, here it comes, and I better add that the list, I've done, only includes one album per band, 

and the number of albums for each year being:

1970  -  9 

1971  -  10 

1972  -  17 

1973  -  12 

1974  -  16 

1975  -  10

If to compare the 70's with other decades, I can tell that the number of albums which qualified to this list, for each decade are: 

This can be considered as a kind of objective answer.

The first part of this list, top 100, can be seen in this thread

http://www.progarchives.com/forum/forum_posts.asp?TID=127673

and the second part, top 100-160, can be seen in this thread

http://www.progarchives.com/forum/forum_posts.asp?TID=127706

(Do you have a wife/sister named Barbara?)

Why? Are you looking for love?

1973 was my favourite year for prog too. After all, that was the year that Tubular Bells chimed for the first time. 

I love Tubular Bells too but I don't think one allbum makes a whole year, although I'm certain there was probably a lot of very good albums released that year also, just as there were every other year.

After all "Dark Side of the Moon" was also released in 1973. That's two heavyweight releases right there.

For some reason I'm not even sure of myself 1971 rang a bell with me (not a tubular one though) as an excellent year for music releases. 

It's probably got something to do with when I really started paying attention to the wonderful wide world of music.

But, I have to say, based on my own listening, while I couldn’t definitively give you one year, I suspect it would be far more recent that anything in the ‘70s. The simple reason being that, like the cosmic universe, the music universe keeps expanding over time. There are so many different sounds and styles now, in addition to those that existed already in the ‘70s.

As much as I own and love some absolutely amazing releases from the ‘60s, ‘70s, ‘80s and ‘90s, I feel like my favourite year (if just one exists) would be on this side of the year 2000 (and probably post 2010). I might have more favourite individual albums from years much further in the past, but as you said - one album does not make a year. Even several albums, for me, wouldn’t make it a year.

Some decades for me are full of wonderful music, of which very little is prog. I love so much music, for example, from the ‘80s and ‘90s, but prog is virtually non-existent within those years, in my collection. The early ‘90s was incredible for anyone who enjoyed that brief period when alternative rock consigned hair metal to history - especially the seeming explosion of bands from the Pacific Northwest (although most were not new, so much as newly exploited by the media and music industry).