Well, you usually can simply move just for a few streets/blocks, it's very unlikely you'll have to move out of the town...But let's imagine if many little shops would be forced to move out of the town because of high rents - wouldn't the town come up with some regulations to prevent that?

Capitalism is fine when it benefits the overall economy, but when it starts self-imploding because of interests of a few, then government jumps in usually - that's why we have anti-monopoly laws, because monopoly hurts the progress...