Price conscious buyers will opt to drive to the bigger, farther away store because it has more variety, and the essentials are cheaper.
I know I do this.
Part of this is overregulation, with zoning and planning departments enacting policies that make smaller retail spaces less attractive to builders and owners, leading to a low supply, and allowing egregious rent for well located small retail.
Yes, economies of scale likely mean that larger businesses can afford lower prices, but smaller businesses also get to avoid some costs (no large administrative corporate departments necessary for a one-location bodega), so the prices probably don't need to be as far apart as they are.
Robinson-Patman is terrible law that’s more or less impossible to enforce equitably. So it hasn’t been.
I hope government representatives have things to say about that.
A world where it’s enforced uniformly and strictly might have some local benefits, but getting the government involved in regulating every wholesale transaction for “fairness” is a recipe for stagnation, corruption, or more likely both.
It’s much better for governments to be principled, and only interfere with mutually voluntary engagements by citizens when there’s an urgent harm to remedy.