It's not even that - people venerate the results of luck. For every "self-made" billionaire, there's untold legions of people who had nearly the extra same formula, but were just a little off. Sure, a lot of them worked hard and had good ideas, but so do tons of people. Somehow it's more acceptable to think these people earned their success more than a simple lottery winner, whose long hours and hard work at their janitorial job gave them enough free cash to buy a ticket.
I think it’s also wrong to attribute everything to luck. The truth is probably somewhere in the middle. Zuckerberg or Gates are certainly very capable people who would have done well under most circumstances. But they were also lucky to be at the right place at the right time and meeting the right people.
I would say it leans HEAVILY towards luck. Given their background and abilities, they certainly would have done well regardless, we have to remember that "done well" can be measured in the hundreds of thousands of dollars. To increase that by another 4 orders of magnitude isn't going to be simply due to being capable.
