It's not so black and white. It's both. Local governments are the gatekeepers but they allow outside interests with sufficient power to rewrite their zoning laws.

A local twp near me as expressed in their meeting minutes let's outside interests redline and rewrite their zoning laws, given enough capital and sway. It's very specific to the municipality, the mechanisms and processes they have in law to change the current ones, and the local base it is comprised of.