Interesting talk. Some parts of the reasoning that might need work:
"if there was no possibility to get rich, there would be no startups".
Does not explain patronage, i.e. people investing in people for reasons other than getting rich.
"without start-ups, there would be slower rates of technological growth".
Prizes, like the Ansari X-Prize, is another model that drives innovation, it can be viewed as a low-risk investment.