Excellent post, tubegroover! We must be about the same age---I'm 65. In the 60's I lived in Cupertino, just over the mountains from Santa Cruz, the beach town mentioned in "Surfin' U.S.A." The Beach Boys were HUGE amongst my friends and I, and remained that way even after The Beatles conquered the rest of America. I wasn't completely sold on TB when they did their first U.S. tour in '64, passing on the chance to see them at The Cow Palace in S. San Francisco. I went the following year, and was rather underwhelmed (The Beatles were not imo a very good live Band).
By the time Pet Sounds came out, I had really gotten into bands like The Kinks, Animals, Yardbirds, etc---tougher, R & B influenced guys. The Beach Boys got left behind, sounding altogether too "boyish". All Summer Long was the last Beach Boys album I heard until Smiley Smile blew my little teenage mind. It was only after hearing SS that I finally heard Pet Sounds, and though I liked it, I liked SS much more. The odd chord changes, the primal chanting and spooky, otherworldly harmonies, the surrealistic lyrics of Van Dyke Parks---it should have fit right in with the psychedelic music popular in '67. But by then The Beach Boys were considered passe', no longer relevant. I could not get most of my fellow musicians to give SS a listen. Contrary to the common wisdom, hippies did NOT have open minds. Capitol Records didn't help the situation, still promoting them as a surf band. Great, just as Jimi Hendrix was declaring "you'll never have to hear surf music again" on his first album!
I like Pet Sounds now, but I love Smile. It would have changed Pop music history, and be considered one of it's crowning achievements. It's never being completed is as tragic as if any other masterpiece were destroyed. Brian's contributions to the BB albums that followed it were minimal, but there are some great songs scattered amongst them, "Surf's Up", "Til I Die", "Marcella", and "Sail On, Sailor" being a few.