> They deserve some fee

Not if the only way to get to the store was through that road. In that case, there are public access laws and it is literally illegal for people who "own" a road to charge people money, if there is an easement.

Thats probably a simplification, but they are called "easement by necessity." rights. So even in your example of the roadway, thats also wrong. They get zero dollars.

Isn't that only to get somewhere else?

My point is in the real world sharing an area with it would mean the other store also contributes tax wise. It's not equivalent to bring up real life if the real life paying part isn't also adhered to; the lack of symmetry is notable. I don't think they deserve to set their price, though (30% is way too high).