In the total absence of regulation, why WOULDN'T a more powerful entity suppress the competitive ability of a rival? If someone is undercutting my widget business with an innovative lower-cost model, and I'm a bigger entity, I'll try to buy him out. In the absence of regulatory power, maybe I'll even burn his factory or threaten his friends and family. Your examples are solid, and I don't argue with them at all- but I don't see the presence or absence of regulation diminishing the phenomenon of monopoly. I think it's simply going to exert itself by different means depending on the conditions.