General aviation is at best tolerated by the public, but as often disliked and feared.
That may actually be true in Santa Monica (with its bizarre and unpleasant culture) and in some other cities, Chicago (e.g. Meigs Field) politics having been driven by similar forces, but it is not in general true among average people in the United States. I think most normal people rather like having light aircraft around.
What's driving the airport closure situation in some US cities, where
more airports are actually needed due to road traffic congestion, is very clear: the prospect of gigantic building permit fees and 1.2% or more annual property tax revenues from whatever is built on that heretofore Federally supported land... which doesn't currently pay much property tax or ground rent. That, plus similar greed among local property owners who would like to flip their homes and move away.
That aside, airports in other US places are definitely disappearing to a degree as the years pass, but I think mainly its because there is less practical need for as many airports now versus then: in most US areas it's easier for an aircraft owner to drive 20 miles to a given airport now than it was to drive 5 miles 70 years ago... when there were so incredibly many US airports. In 1950 there were four GA airports within 12 miles of my house, but the roads to get there were not so good. Now I drive 20 miles in just a few minutes, front door to hangar door, and the facility is much better than any of those 1950 airports. I think big picture, in regard to most areas outside of those big cities like LA where they actually need more GA airports to meet demand, consolidation of airports is a rearrangement to better match the infrastructure on the ground.