There are plenty of discount stores that are working their way in, e.g. Dollar General, Family Dollar, but they don't have control over the rents either and in alot of larger cities they also are facing opposition from the small businesses that would be out of business since they would have no chance of competing on price at that point.
Whether having every small bodega or other small retail shop replaced by 7-11, Dollar General, Family Dollar, etc. and yet another avenue for access to the middle class shutdown is worth the affordable prices for everyone else is debatable. I can see both sides of this anyways.
I think predatory practices will decrease because people will be voting with their feet, no longer constrained by where they live.
Economy of scale. Given fixed size of the UBI check, you want to live where services are cheapest. And services will be cheapest in places where more people are serviced together, because that cuts down on distribution costs and other such overheads.
Also, areas where people who have more money than just UBI live, would have higher prices simply by virtue of there being more money in the local economy. This isn't really dissimilar from the existing arrangement, where rich areas are expensive to live in, and so there's natural geographic segregation. But UBI would boost this into high gear.
To clarify, I am a strong proponent of UBI personally. But I think we should be really careful with these kinds of unintended side effects, and try to anticipate and manage them before they cause a bigger mess than what we're trying to address.
Also, have a look at this: https://medium.com/migration-issues/should-a-universal-basic...
Huge retailers today offer worse prices, lower quality and lousy service because they can get away with this, being the only game in town.
At the same time, rent in cities skyrocketed, making low-density and rural places much more affordable.
We now know that economy of scale peters off at some fixed scale.
Also not everybody can afford to move.
Basic income is precisely about "afford" part.
Those who won't move will benefit too because landlords will have to work on retention.
This assumes that basic income either includes an allowance for moving or contains enough of a surplus over basic needs that savings can be accumulated.
He can try, but then he'd lose out to competing landlords who don't raise rents as much (or at all). It's like gas stations; owners know that people are willing to buy almost as much gas at $3/gallon as they are at $2. But when the price of oil falls, they can't just keep charging $3, because their competitors will charge less and take all their customers.
EDIT: To add to this, it's worth pointing out that many corner stores in low income neighborhoods already take advantage of peoples' lack of access to easy transportation to charge unusually high prices for common convenience store items. It's already more expensive to be poor, and I think basic income would just increase the predatory practices that are already happening.