Robert Johnson? Lead Belly? Miles Davis? Woody Guthrie?
Oh the Beatles. Don't get me wrong, I dig them and I know they're important, but come on. Without the blues and folk music of the first half of the 20th century, there'd be no rock and roll for the Beatles to play.
I'm not discounting the contributions of those you mentioned. It's also questionable whether any of those artists or any subsequent artists (including The Beatles) would have been able to make the marks that they did without the development of the impressionistic music of the late part of the 19th and early part of the 20th century such as Ravel and DeBussey, the ragtime music of Scott Joplin, the delta jazz of Louis Armstrong, the musical compositions of George & Ira Gershwin, Duke Ellington, Count Basie, Cab Calloway, Hoagy Carmichael.....without the big band compositions of Glenn Miller and Tommy Dorsey or the country/western contributions of Jimmie Rodgers, Hank Williams or Roy Acuff or the bluegrass music of Bill Monroe. One could also include John Lee Hooker, John Coltrane, Carl Perkins, Bill Haley, Chuck Berry, Buddy Holly as well as Elvis and Jerry Lee Lewis, Johnny Cash or.....Bob Dylan (now one could argue that
he might approximate the same level of influence that the Beatles did!)....and many others who are very deserving of mention.
My point is that the advent of the Beatles marked a distinct and very identifiable transition into a totally new genre of rock 'n' roll, generally called "rock", that is still in vogue today in an evolutionary form, nearly 50 years later. Their influence on music throughout the last 40 years of the 20th century is unsurpassed by any other artist so, yes, I stand by my statement that they are the most dynamic and important single influence on the evolution of music since Beethoven. That takes nothing away from the many other great artists that preceded them including the ones that you mentioned....or those that followed them (including the immortal Michael Jackson).