That's an awfully long way to reach for an explanation of why teachers don't make money, when "supply and demand" was sitting right in front of you. There are lots of teachers. It's not very hard, not particularly more so than many other careers. There aren't a lot of top celebrities, since that works on the competition model (like sports).
If it makes you "feel" any better, there are lots of computer programmers, too. Saying there is a lot of something doesn't have to mean it's "easy", just... that there's a lot of it.
I'm not seeing where some sort of complicated explanation is necessary.
Again, why do I have to reach farther than "the nature of the Gaussian distribution says there will be outliers"?
(Also... "there was only one Mozart" is rather more hero worship than truth. There are many factors that coincided to make Mozart, and I fully expect there have been multiple people since then that have been every bit as talented, but didn't have the same factors coming together. Going into that would be a long, long post about music theory and music history, though.)
If it makes you "feel" any better, there are lots of computer programmers, too. Saying there is a lot of something doesn't have to mean it's "easy", just... that there's a lot of it.
I'm not seeing where some sort of complicated explanation is necessary.