https://www.google.com/search?q=supermarket+chain+buying+pro...
Next time when your personal incredulity finds something unbelievable, instead of assuming you must be right and the other person is wrong, just try a simple google search.
In my area property is constrained and in high demand so deed restrictions that only block one industry don't inhibit sales much.
Our population is not "super low"; our county has a third of the population of the largest city in our region of the US.
> people can buy real cheap at farmer markets where they just sell direct
Just because I said "rural" doesn't mean there's farmland.
So unless you can post a source of your claim - euro grocer pissing away millions by devaluing rural properties, the search link you posted so far quite literally proved you wrong.
Likely, prices are high because population is super low, and people can buy real cheap at farmer markets where they just sell direct. European grocery stores buying up property in some rural area? That's called a conspiracy theory - blame problems of low population and no easy highway access, because we refuse to vote for taxes that pay for infrastructure on those scheming socialists an ocean away.