I think the answer to this is to adopt Land Value Taxes. This would naturally incentivize property improvement and dis-incentivize people from owning large swaths of unproductive land. Communities would grow upward before they grow outward. Infrastructure costs would drop significantly and communities (over time) would become more walkable.
It'd be fantastic if we could persuade some local governments to try this and work out the bugs. If it went well, it could be adopted by more and more locales.
1. Approval voting becoming widely adopted. This would go a long way toward mitigating the hyper polarization in politics in America (and likely elsewhere as well). Electing politicians with broader approval means legislation would likely move more quickly.
2. Moving to a Land Value Tax system in America. This would organically help us transition to a culture that builds up instead of sprawling out. This could lead to tremendous reductions in things like municipal infrastructure costs, transportation pollution, reduced mortgage/rent prices, etc.