I actively worry about this and I'm skeptical of your thesis that people will naturally reach a point of "enough really is enough". Even in your own story you

I actively worry about this and I'm skeptical of your thesis that people will naturally reach a point of "enough really is enough". Even in your own story you are saying that you have enough now, but up until this point your expenses have grown to meet your income. The same is true for me, and I worry that it will always be so. I tend to believe that the majority of people will continue to grow with their income to very high numbers. I don't see the majority of people making $1M/year living a comfortable $250k/year lifestyle and investing/donating the rest. Some yes, but certainly nowhere near 50%.