> But somehow people still buy food and shelter even though they could put their money in VTSAX instead and get 7% returns.
Silly people, needing a roof over their heads and nutrition.
> We could use a world with more saving and less consumerism.
Everyone saving more would be disastrous for global human welfare. It won't preserve resources in any meaningful way and would set society back generations. If that's your goal, great.
But what we need to do instead is shift toward consuming sustainably. That might mean consuming less in some instances, but in a many cases it means consuming differently, especially in how we consume energy.