Except that the structures we have in place have time horizons even shorter than a human lifespan. Stock market runs on quarterly reports, governments run on election periods of a couple years. The organizations we give the most power to just don't operate using long term incentives. And then democratic processes don't even let everyone who is currently alive vote, much less those who aren't born yet. It's a problem that largely requires unselfish thinking which makes it extremely difficult to incentivize.