A lot of people would care, that’s the issue. Even if you personally have achieved an enlightened state where you’re perfectly able to voluntarily forego trying to do and acquire things that are contributing to an unsustainable society, it doesn’t mean that you can extrapolate from that and construct a stable system where everyone else does the same.
Human beings are greedy and shortsighted, and they especially want to have more than the people they surround themselves with. Any sustainable solution will need to take this into account.
Life isn't a race to consume everything as much and as fast as possible