[Spike Knotts]

I think an enterprising businessman could make some money leasing/renting these abandoned developments (when possible) and staging road/rally races on the property.

It would also be a nice way to build a motorsports park on the cheap.

[ConservativeWarrior]

and staging road/rally races on the property.

Looks like someone's already started the fun. Look in the lower-left corner of the first photo.

Incidentally, there is a 55-and-over development near my local airport that has been 10% complete for 10 years. I used to off-road on the property, then a developer bought it and ran all the roads and utitlities.

The 10% that built realized they got a good deal on a home adjacent to an airport. They tried to get the airport shut down, but ended up merely creating publicity for their situation. As a consequence, none of the other lots sold. The lots are all dirt and weeds, with a handful of elderly people stuck in their homes.