This is a nonsense example. The cost to do business in a small town is much higher because they have to have their products shipped there, which increases the cost (if it cannot be made locally), they don't have the economics of scale of a chain store, etc, etc. So the prices are going to be higher. If people want to live in a small town that is far from other towns/cities, then they need to accept that some costs are going to be higher. There's no reason for the rest of the country to subsidize their costs when they willingly decided to live there. If someone builds a log cabin in the middle of nowhere, it's not incumbent on any grocery store to open up to serve that 1 customer, nor for any other services to be provisioned.
If you owned the only grocery store in town and started charging $10 for a banana, a combination of 2 things would happen: 1. ppl would stop buying bananas, and your bananas would go to waste. 2. Someone else would start selling bananas at a cheaper price. It does not require a grocery store to do that, many convenience stores sell fruit, and it doesn't have to be a convenience store, anyone could sell it. All it takes is 1 person who is traveling into the town once/week on some other business, and they will start bringing bananas to supply to a seller. If the price is $10 because that is the actual cost of obtaining bananas in that town due to supply constraints, natural disaster, a banana-eating insect epidemic, or some other factor, then forcing the business to sell it lower means they are making a loss on it, which does not make sense for anyone, because they are either going to stop selling bananas or the store will go out of business if they are forced to sell everything below cost.
Price gouging only happens when there isn't competition, and that only happens when the government restricts competition.