There's BOTH factors, but the master-plans and zoning that require sprawl by forcing major separation between residential, commercial, industry etc. — all that was top down. And by top-down, I mean at the local city planning level, not the federal level per se… except the federal policy helped finance the sprawl…
Also, these big developers are sorta top-down too. They are big powerful entities setting things up for the people who actually use the developments instead of iterative development.
There's a ton of ridiculous patterns built into development that relate to the way it is financed etc. and that along with zoning etc. creates insane sprawl.
https://www.strongtowns.org/ does a remarkable job at addressing all these issues, not taking a dogmatic top-down or bottom-up or whatever view.
Also, these big developers are sorta top-down too. They are big powerful entities setting things up for the people who actually use the developments instead of iterative development.
There's a ton of ridiculous patterns built into development that relate to the way it is financed etc. and that along with zoning etc. creates insane sprawl.
https://www.strongtowns.org/ does a remarkable job at addressing all these issues, not taking a dogmatic top-down or bottom-up or whatever view.