The solution is obvious and not going to happen. Extra tax, super cheap rent with conditions: Minimum number of products, product diversity, open x days per year (etc?)

30 years ago there was this lovely shop here full of hand crafted wooden dolls and beautiful wooden statues about the size of a garden gnome. They were reasonably expensive but an absolute joy to look at without buying anything.

I don't think selling tickets like in a museum would work for a place like that. If they tax me 10 bucks the city could buy the building and continue to lure me into town.