Almost - I believe it is a predominantly retrospective appreciation. 

In 1966 singles were still the dominant format for music and while Pet Sounds is now regarded as one of the first albums to challenge that, its success (in the UK at least - it was slightly more popular in the UK than the USA) was due entirely to the success of the four Top-5 singles they released in 1966 (Barbara Ann, Sloop John B, God Only Knows and Good Vibrations). For the British record buying public Pet Sounds was just a vehicle for two of those hit singles and I posit that the cult-like status that it has now was not that profound back in 1966 (in much the same way I have previously argued that Smile's near-mythical status is a much later phenomenon that had no effect at the time) and is a retrospective assessment of the album as a stand-alone entity. The influence of the Beach Boys on British music and musicians is more to do with those four singles than any Beach Boys album and that was mostly due to the close-harmony vocals and not the musical instrumentation and arrangements. [I know this is a persnickety splitting-hairs piece of pedantry, but in 1966 albums were nowhere near as "influential" as singles - singles buoyed-up album sales].

If you look at the success of the Beach Boys in Britain you'll notice that those tracks that sold well weren't the Californian surf & hot-rod songs. Britain (and Europe) does not have a surf scene or surf music and the Beach Boys were regarded as a purely American thing and something of a novelty. While much is made now of the Beatles/Beach Boys "rivalry" (if it existed at all, and I question that it did, I think there was some mutual respect between Wilson and McCartney but not much else) then it was not a sales and/or popularity rivalry in the same way as that between Beatles and the Stones, and even if it were just artistic "rivalry" it was non-existent until the Beatles released the non-singles album Rubber Soul (which Brian Wilson has said inspired him to record Pet Sounds).

However, Barbara Ann was the break-through song for the Beach Boys that broke their surf image over here (and Good Vibrations was the culmination of that success):

Notice now the effect of Barbara Ann on their album chart positions from Feb 1966 onward (including the retrospective chart entry of Surfer Girl four years after its release):

Something we can only speculate upon because even if a musician professes to be influenced by someone they rarely say exactly how that influence was employed. Subconscious or overt is a key point here as any analysis is going to be retrospective and fogged by hindsight because recognising a possible influence in a particular piece of music does not mean that it was a direct influence.

The problem here is there weren't any directly influenced Beach Boys inspired bands for us to call upon, so all and any influence is subvert and nuanced, which makes it all very subjective and speculative. Even if we pick on the vocal harmonies (and here many late 60s and early 70s bands adopted vocal harmonies), it's difficult to say that any one band's approach to harmony can be directly attributable to any other band.

Previously you called them Art Rock but here I would reduce that specifically to my pet subject: the closely related and often overlooked pop genre of Barque Pop, (i.e. Proto-Art Rock), which for me puts them in the same echelon as The Moody Blues, Procol Harum and The Move, though none of those can be said to be influenced by them.

This thread is in  http://www.progarchives.com/forum/forum_topics.asp?FID=41" rel="nofollow - General Music Discussions  ergo this site's forum is not wholly dedicated to prog and therefore this thread is not about Prog, in the past you have professed to not liking the Beach Boys so I do wonder how this morphed into an appreciation of Pet Sounds. The problem with discussions of genre is that they only end well when the person who triggered the discussion gets their own way because that's the only way you can get them to stop going on about it; such discussions are not esoteric exercises, they are esoteric discussions.

Regardless if this is a non prog appreciation thread. It concerns music and the possibility that the OP is a prog fan is quite high. Associating the Beach Boys with proto prog would be a sign of appreciation. Unless someone does not like them, then the opposite would hold true. I'll rely on my calculated guess that the OP is a prog fan and stand fast. 

 

Btw, Beach Boys forever! Brian Wilson is a genius!  (Just clear up any lingering doubts.)

I'd like to hear those reasons anyway, just out of curiosity.

Plus the fact that Wilson mentally couldn't finish the album gives me pause to think that his brain was not firing on all eight musically and emotionally, even early into starting the Smile recordings. This is conjecture on my part, but it guides my feelings regarding the Smile material. The Smile material was also highly mythologized, IMO, into being something much greater than it actually was. 

 

There's also early alt version of Heroes and Villains that pauses while Brian interjects another supposably humorous line "You're under arrest" followed by a ricocheted bullet sound. Again, not very funny, IMHO.