You're right, of course. He was at the right place at the right time. One could call that luck, but if you think about it all four of them had equal amounts of luck because if any of the pieces had been missing it would not have been nearly what it was. Same goes for their luck in stumbling upon George Martin, who was producing comedy records at the time but turned out to be exactly what they needed. It does seem that, for whatever reason, there was some divine intervention associated with the Beatles.
Everybody just has fun ragging on Ringo because he was the drummer and didn't have the writing and singing talent the others had. Then when he cops an attitude like this, it's easy to say, "Hey, you're just Ringo." It reminds me of my two favorite drummer jokes:
1. Q: What did the drummer get on his IQ test? A: Drool
2. Q: What's a drummer? A: A guy who likes to hang out with musicians.