My thinking is that there's also physical health issues and other issues that make physical activity less viable. Human travel (walking/biking) would be a big help*, or just more time/space/money/comfort/motivation(s)** (alternatively: if healthy options were more of a norm/incentive rather than a lucrative market to chase) which is even less likely than changes to zoning/density and infrastructure.

In any case sure, improving someone's life in 1 aspect will provide benefits... but is anyone actually going to help with that or is it going to just result in more of the same platitudes that are already heard? I don't think any study has much chance to create policy in the USA any decade soon.

*=That's from experience... I'm in a semi-rural area, started biking right before the trail closed for renovation ~6months ago. Still closed, no ETA other than "early 2024".

**=Aside from health/personal/travel reasons, maybe it's for a hobby. Getting something out of the activity (money, electric, usable mechanical energy) would be nice if it weren't a problem of cost/storage/loss/logistics etc.

EDIT: And I should say Bowling Alone is in force here too, but again money is probably a big part of that too.