Your problem is that you're associating the biggest most overhyped entrepreneurs as being the typical entrepreneur. And they indeed do hit huge luck. So you're right there.
What the media doesn't talk about -- are the thousands of founders running profitable companies in the tens of millions or even low hundreds of millions.
If you do something of value to society, the world will make you rich with a smile on its face.
Said no teacher, cancer researcher, etc. ever
Yes, he got lucky. (Which I already acknowledged.) But successful founders aren't "just lucky".
If you look back at his history, he had a string of very college-student-useful projects before Facebook. He knew he was onto something. Assuming that he would have the same kind of curiosity/initiative/wtv in 2014, chances are he would find new problems to solve.
I'd say on the order of 1. 1 in a billion 2. 1 in 100 million. 2. 1 in a million.
Sure he is smart and driven and has had every opportunity available to the one guy on planet earth who will achieve what he has. But that doesn't mean he's qualitatively different than the millions of others equally intelligent and talented who didn't buy the winning ticket.