Sometimes the government is forbidden from buying land but nothing stops an individual or charity.
Third option:
Monks want to put up some minor tourist attraction, put in some parking and hand rails or engage in literally anything, doesn't really matter what since it's all invariably regulated near water. Bureaucrat who doesn't "get it" says no this is a special site if you want to do that you need to do XYZ first or GFY. Monks say we can't afford XZY, that would make this whole thing a nonstarter or defeat the point. Site languishes for a decade or two because while the subsequent bureaucrats may know what's right they can't necessarily ignore what the first guy said without sticking their necks way out. Eventually the monks find someone to help them out who gets the state to take it off their hands. Maybe they monks get a fair deal, maybe they're losing their ass, who knows.
This fact pattern is really common with redevelopment of eyesore unoccupied buildings in prime locations so it wouldn't surprise me to see it going on with some natural site like this.
This has nothing to do with government and a lot more than nothing to do with sneering jerks who dismiss the potential for systemic failures and stupidity by handwaving it away as "catastrophizing" enabling the systems to produce exactly those sorts of failures. Any bureaucracy can screw up in the manner I'm describing, insurance, bankers, it's not just government.
Bad outcomes are very, very, very sticky because the people that rise to positions that could undo them don't get there by being disposed to such actions. Some non-standard organization (a bunch of monks who aren't pro RE developers) with a nonstandard situation are high on the list of places these failures will happen. They submit something to some agency and use the wrong words, some dude who doesn't see many of these cross his desk denies it on some grounds and you've just locked in a problem that's gonna cost a lot of money to undo and monasteries aren't typically engaging in the sort of high dollar economic activity where they can just fight through it knowing it'll be paid back later.
I'm not saying that's what happened here but this is exactly the kind of place it could happen.
>(Buildings in prime locations aren’t equivalent.)
There are old mills on the outskirts of town and then there are historic mills on the river on main street.
There are overgrown farmers fields and there are forests with waterfalls in them.
See what I'm getting at?