A lot of fair points, and I fully expected to see @onhwy61’s argument made. Sweetheart Of The Rodeo was big in my small circle of friends (my senior year band included a coupla songs from that album in our repertoire, as well as some Buffalo Springfield songs), as was Dylan’s John Wesley Harding and The Flying Burrito Brothers’ debut.
As for The Band coming out of nowhere with a unique sound, well, not to be argumentative, but they actually did. I have numerous times reminded everyone that Dylan began recording in Nashville in ’65, but that was not because he was "going Country", it was because that’s where the musician’s he wanted to record with were. In 1965 the members of The Band had no idea who Bob Dylan was, nor did they care (their idea of a singer was Bobby Blue Bland, Ray Charles, Muddy Waters, Fats Domino, Little Richard, Hank Williams, and The Louvin Brothers). While the other groups mentioned above had some of their same influences, none shared The Band’s deep Rockabilly, R & B, Gospel, and 1950’s Rock ’n’ Roll roots. Springfield had three singers---as did The Byrds and Moby Grape---but none had a singer of Richard Manuel’s caliber. IMO, of course. And none had a musician of the caliber of Garth Hudson.
Whereas the Sweetheart album was deliberately, overtly Country, in Music From Big Pink and the brown album, The Band wove the thread of their Hillbilly influence into the entire tapestry they wove. It didn’t obviously stick out (though they did include Lefty Frizzell’s hit "Long Black Veil" on MFBP), but their music was subtly infused with that influence. Levon Helm was listening to KDIA out of Memphis, Rick Danko The Grand Old Opry, and their playing and singing absolutely reflects that. The other groups has far less character in their voices than did Levon, Richard, and Rick.
But ya’ll are STILL missing my point! Eric Clapton and Bruce Springsteen (and Nick Lowe) were all very aware of The Byrds, Buffalo Springfield, and anyone else you care to mention. And yet it was Music From Big Pink that knocked them on their asses, not those other’s albums. You may agree or disagree with Eric and Bruce, but that’s beside the point.
Clapton didn’t disband Cream and think "It changed my life" in reaction to hearing the Sweetheart album, The Flying Burrito Brothers’ debut, or any other album you can name, but rather because of MFBP. Springsteen didn’t react to hearing any album but MFBP by thinking to himself "and everything changes".
For anyone who didn’t (or doesn’t) react to Music From Big Pink in the way that Clapton and Springsteen did, so be it. And you can agree or disagree with me (and Clapton and Springsteen) if you wish, but I’m here testifying to the truth of the cataclysmic effect MFBP had on the 1968 Rock ’n’ Roll community. George Harrison flew from England to San Francisco to attend The Band’s 1969 debut show at Winterland. He did not come to America to see and hear Buffalo Springfield---or anyone else, only The Band.
For Clapton, Springsteen, myself, and a lot of musicians I know, there is a musical dividing line as dramatic as B.C / A.D.: Before The Band / everything that followed in their wake.