The Beatles are a vital cog in the 60s but, that's it, they're a cog.
Without the 60s they wouldn't have been the biggest group in the world, someone else would have been.
The 60s were made for the biggest pop group in the world (Pirate Radio, TOTP, RSG!, 4 weekly music papers, pre-stadium rock, pre-logos, singles more important than LPs), no other era.....so, if born 10 years earlier, they'd barely have existed, if born 10 years later they'd have been someone ho-hum who already had the road-map that the biggest group in the world, erm, The Beatles, had created! (e.g. Roxy Music, the clash et al).
I reckon the 60s started much sooner than most would acknowledge (Lonnie Donegan/Elvis in the mid-50s or even The Festival of Britain in 1951) and also ended much sooner, the writing was on the wall as early as 1968, although there are quirks (e.g. Nick Drake's 'Pink Moon' from 1972 is, for me, more a product of the 60s than the plodding, 'ahead of their time', Led Zeppelin or Cream).