Grave sites, once sold and occupied, are intended to be occupied for a very long time, and their sale can't easily be negotiated if more valuable uses turn up. So there is less turnouver than in other kinds of real estate, with predictable consequences, as this Globe article attests: Supply limited, demand eternal, graveyards fill up.
"Provincetown’s shortage, while unusually acute, underscores a broad and burgeoning problem in the crowded Northeast. With land expensive and limited acreage available in large swaths of Eastern Massachusetts, budget-crunched communities are struggling to buy sites for new burial grounds as their existing cemeteries fill up."
"In Provincetown, many who have reserved burial plots are relative newcomers to the town, and in response, town officials this week passed a rule restricting burial plots to those who have maintained a principal residence for at least two years. Still, that was a short sojourn, some said, for a chance to spend eternity in a slice of heaven.
Said Lemme, the cemetery supervisor: “We might have to make that a little stricter.’’ "