Right @tablejockey, The Beach Boys appeared during the era of the Girl Groups, The Four Seasons, the teen idol Pop singers, instrumental Surf music (I loved The Ventures), Paul Revere & The Raiders, etc., and they continued to be associated with that era after the British Invasion killed the careers of almost all those American entertainers.
But Brian Wilson was no mere entertainer, as everyone in the music business knew. He was progressing musically at light speed, and his Pet Sounds compositions and production (unlike The Beatles, who relied upon George Martin, Brian did it all himself while the other Beach Boys were on the road) took everyone by surprise, especially Paul McCartney. But I was just a 14-year old kid, oblivious to all of that.
The British Invasion groups were much "tougher" sounding than the angelic Beach Boys, Brian’s falsetto vocals harkening back to the sounds of the early-60’s. The All Summer Long album was the last of theirs I bought, ignoring the Today and Summer Days (And Summer Nights) albums. I was listening to The Yardbirds, The Animals, Manfred Mann, etc. and of course The Beatles and Stones.
As far as I was concerned, The Beach Boys were history, no longer of interest. The new American bands---The Byrds, The Lovin’ Spoonful, The Paul Butterfield Blues Band, Buffalo Springfield, Moby Grape, The Airplane, etc.---and then Cream, Hendrix, and Procol Harum---are who I was listening to when "Good Vibrations" appeared on the radio. I dug it, but didn’t even consider buying the album it was on. I considered The Beach Boys a singles Pop group, not a Rock band.
Then in early-’68 a guy I knew at school gave me copies of the Smiley Smile and Wild Honey albums. I got high and listened to them, and couldn’t believe what I was hearing! I later read the article about the Smile album in Crawdaddy Magazine, written by Paul Williams (not the singer-songwriter), and thus began my obsession with Brian Wilson. That 2-part Smile article by Williams later appeared as two chapters in his great book Outlaw Blues, a must read.