Large businesses can operate at a loss that small businesses cannot sustain. They do this to strangle out competition. Then, after they’ve established a monopoly or oligopoly, they price gouge customers, reduce COGS resulting in inferior product but higher margins, etc.
I’m surprised that this is news to you. This is basically the foundation of antitrust law. Like, this is extremely common knowledge to the point that it mystifies me that you are not aware of it.
Come on mate let's be serious here. Monopolistic actions can stop local competition through completely legitimate means (such as temporarily selling products at a loss in a way which smaller competitors cannot due to access to more palatable capital funding for instance). After a certain level in size, competition is rarely about the product alone