In a free market, I think monopoly's in general will almost certainly develop over things that are scarce. (Car's, food, computers, etc.) This is not a good thing, because it centralizes power.
This is patently and provably false. The computer market is one of the least regulated on the planet. Cars have only safety and emissions regulations to contend with (and many companies voluntarily exceed those regulations). Food, similarly, has only health and safety regulations, and a few labeling requirements. You chose the worst possible examples for natural monopolies, since all of those industries show robust competition, in a largely unregulated (free) market.
Actually I was not talking about natural monopoly's. I was talking about monopoly's from integration - why did you choose to let that one out?
Plus, I'm pretty sure that all of these markets are regulated, since monopoly's are illegal in the US.
http://en.wikipedia.org/wiki/United_States_antitrust_lawAlso, it is illegal to kill your opponent, so that's another regulation. Sounds silly? The drug market is truly unregulated. The free market turns out not to work very well there. Violence works.