And amazingly we still have businesses that compete and don't price all their competitors out of business. So I don't think this is an obvious conclusion.
Or it could actually have nothing to do with regulations. Something called imperfect competition: very few people want and sell the exact same thing. That makes it very difficult to sell superior products at lower cost.
As far as I can tell it is very difficult to prosecute for predatory pricing in the US. This doesn't particularly matter, since it is an awful idea and almost no businesses would do it anyway.