because governments generally suck (so do citizens) and only really think about protecting themself first and foremost. what if a kid got hurt from a non park-certified plot of land..people would sue and probably win. no safety signs that nobody reads, no disclaimers. it's just a liability game is all. it's stupid but people can't use common sense so things lay unused until years of fighting to get some stuff installed, if ever.

https://case.edu/ech/articles/l/lakewood-hospital

Looks like the city currently owns it, according to the cuyahoga myplace

https://myplace.cuyahogacounty.gov/

Search for 14519 Detroit ave

There's a big partly filled-in pit under there they need to contend with, makes it tough to develop.