In few words: the Beatles are legends not thanks to their 1st eras. Good thing he's acknowledging the fact that they'll never be as sonically developed as TB. Under Simon Cowell it seems unlikely that, even if they wanted to, they will reinvent themselves. Besides, the Beatles wrote their own songs and did some of the production.
But hey, at least they can sing (which is nowadays a rarity). But they're not as much of a phenomenon. We'll see in 10-20 years.