You make it sound like selling all at once and flooding the market is the only option. He could slowly sell off shares over many years and thereby exchange personal power at amazon for tangible good in the world. He choses to maintain his position because that's where his priorities are. He's within his rights to do that, but let's not pretend one of the most powerful people in the world has his hands tied.
Isn't he doing exactly that with Blue Origin? AFAIK he's selling about $1b of AMZN stock every year to fund it. He's also recently pledged $10b to fight climate change.
