It's estimated he Inherited $40M http://www.politifact.com/florida/article/2016/mar/07/did-do...
Trump himself claims he started off with "a small loan of 1 million dollars" https://youtu.be/mkKBXJRySFw?t=20s
https://www.youtube.com/watch?v=TXEOFHf1q9A
On the other hand, that's less than the investment funding I've seen to some folks on HN, and it's the same amount of capital that would be required if you wanted to open a McDonald's store [1]. But I think a majority of people would regard that as starting from a wealthy position, and certainly not bootstrapping anyway.
So half of SV should still be safe.
More importantly, if I have the choice between roughly equivalent outcomes where one consists of decades of busywork and the other consists of taking a small part of the money and doing good in the world, why in the world would I want to be building a real estate empire?
Of course, for Trump the reason would be because he's a narcissist who needs to see his sense of self-worth boosted by seeing his name slapped onto buildings in giant letters and his face in the news. But for someone who wants to merely lead a good life? You take out however much you need to actually make a positive impact, and leave the rest in index funds.
That said, I'm not rich so I don't understand the system and why things need to be the way you describe. Please provide some insight.