It's loads of reasons i reckon. Heres my half baked reasoning!
First and most basically the name. It's clever, it's not a real word. Well advanced for its day and they're instantly the best named band to take on what's to come in the 60's. Look at the other bands names - they're good for stereotypes but culturally Beatles name literally means music. Its also the first time they attribute creativity to dreams which in and of itself adds to the mystique.
A Band. They had big bands and singers - performers like Jerry lee Lewis who had bands - and they say 'The Crickets' were the first real band - you can see the influence. They were formed in '57 - only a couple of years before The Beatles but Holly died in '59. So in a lot of peoples eyes they were the first 'band' people had ever seen.
Cultural Influence. From the very first moment they broke out they had an identity - and fused hit songs into fashion and art and not only did it first with the mop tops and suits, they did it again a few years later with Sgt Peppers, psychedelia, and leading culture, and then again with counter culture.
Mainly though it's just the actual songs, the development of albums, building up and breaking down genres and the metamorphasis of their sound. Thats not even touching on the incredible innovations in recording and mixing techniques. You’d get an entire lifetime career out of a song like ‘Revolution’ when for them its just another tune.
And finally, the career. They smashed out apprentiships, graduated to superstardom before anyone, worked their absolute socks off, borrowed heavily, paid it back in spades, got way too big for their boots, refused to tour, pioneered ownership of their material (eventually) and broke up spectaularily.