Yeah this isn't really accurate. Cemeteries regularly disenter bodies of people who don't pay. They will send letters to next of kin and dig you up once no one answers. They then resell the plot. They even double stack caskets in some cases. Some cemeteries(hollywood) have perpetuity funds/investments, evergreen did not. You can still buy a plot in Hollywood today, it's most likely a used lot.

I still think burial grounds are the worst possible use of riverfront downtown land.