I mean the slots themselves would take up an area in which any car that enters is despawned, factor in the number of businesses that might want a private spawner and there wouldnt be enough space for people who just like to sit in their cars
Ontop of that some people might prefer to actually have their car parked and visible instead of needing to be pulled out, owning a 3 mil car and not having anywhere to park it without the risk of getting heckled by a cop or rammed into by some popov retard going 600 mph down the road