As far as the Beatles being the "uncommon singer/songwriters", you'd be incorrect. Carl Perkins and Chuck Berry were doing long before they were. They also were the KEY influences in the Beatles.
Fine, but nobody said they (the Beatles) were the first. I was saying that it was uncommon, not unheard of. The massive chart success that the Beatles had, with their own material (along with Brian Wilson's big chart success with the Beach Boys) made it much more palatable to the record companies ( who decided what got released) to allow their artists to write their own tunes. Within a few years, it was pretty common. Before that, the music business machine had pretty much stifled artists, except for a few of the big names. And it's probably no coincidence that the half dozen or so big names cited by "Radiohead>You" happen to be the main ones that have endured through the years, even though they only accounted for a small percentage of the top hits of the times.