[drawnwren]

Bezos frequently speaks about efficiency of deploying capital. My guess is he doesn't believe he would get 10x results from 10x investment.

[Tepix]

I'm sure that there is some speedup when he starts spending more than $1 billion. Given that his net worth reached $150 billion it seems like it's safe to go to $2 billion/year without running out of money during his lifetime.