From what I understand, in the free market system we consider things to be anti-competitive, anti-consumer, etc. when a corporation has some kind of market domi

From what I understand, in the free market system we consider things to be anti-competitive, anti-consumer, etc. when a corporation has some kind of market dominance acquired through earning the trust of consumers, and once they have obtained that trust, they abuse it by imposing a set of self-serving conditions on the market which serves their own interest in some way at the cost of some other player in the market - either consumer or competitor or someone else. To enable this countries and regions have drafted laws to govern what business and trade practices are permissible. Some non-rhetorical questions out of curiosity because I genuinely don't know: Is it illegal for supermarkets to only partner with certain brands and carry their products over those of their competitors? If there is only 1 Walmart within driving distance of 50,000 people, and that Wal-Mart chooses to throw out all toilet paper brands and sell their store brand, is this allowed under current law? What if they allow the brand to stay if they pay an additional whimsical commission to Wal-Mart? Is that legal? Is there something that makes the App store different from the physical store equivalent? Putting aside the letter of the law, does it violate the aforementioned "spirit" of the law? i.e. ought there be laws against this kind of behaviour? I am sure there are good arguments for both sides.