I'm near several "used to be" race tracks.
Both Ontario and Riverside are now retail/industrial areas (and have been for some time).
The long gone Orange County Speedway is all houses.
The idea of OC Country Speedway (a drag strip) still being there would be truly preposterous. Drag racing and Irvine don't mix. Save, you know, on the streets at with those crazy kids from Newport in their BMWs. At least those only kill people vs something annoying, like make noise.
We still have the Pomona Raceway. And that area is all built out of long term residents. Surrounded by the fairgrounds and an airport. I don't see it going anywhere (unless NHRA goes away). I also only think they do two events a year (large NHRA nationals) vs the weekly drags that someplace like Irwindale was doing.
Fontana was built after Riverside closed.
What really amazes me is how few events were at Fontana. MotoAmerica never came back, I dunno if that was due to deteriorating track quality, or lack of market in SoCal. Yet, we still have the Long Beach Gran Prix every year. And with the reduction of the track size, there will be no more open wheel racing I don't think at Fontana, no road course, just a small oval for, I guess, a NASCAR event each year.