No one is forcing you to sell. There are lots of people that are perfectly happy in the Walmart free town. There are people that are coming because it has no Walmart. And there were no contract signed that there would be a Walmart in the vicinity.

No I'm not. In the smartphone case, you've bought your iPhone, but you're only allowed to "furnish" it with items from the Apple App Store. If you don't like the Apple App Store, you're screwed. You have to sell or ditch your iPhone, and everything you've bought for it becomes worthless.

In the Walmart case, you've bought your house. Presumably up until now you've mostly relied on Walmart to furnish it, and to buy groceries, etc., etc. Walmart disappears. Your existing furnishings are fine and still work. You can buy more furnishings at other stores, and they will work just fine in your existing house, with your existing furnishings. You can buy groceries at another store, and consume that food just fine in your existing house. Also consider that Walmart has online ordering and ships things; if you really want to continue to get some items from Walmart, you can still do so.

Sure, if you're unwilling to take the entirely reasonable step of finding alternatives to Walmart, I guess you'd have to sell your house and move to a town that still has a Walmart. But that's... a pretty ridiculous course of action to take, honestly.