[dragonwriter]

> So company profit margins should be capped? At what level and how would that work exactly?

That a competitive market drives prices to zero economic profit is a fairly basic result; no active measures besides the existence of competition are necessary for this.

> What about all other stuff?

Yes, this applies in all competitive markets. If it doesn't apply in a market, there is a constraint on competition causing it.

[Wytwwww]

> prices to zero economic profit is a fairly basic result

Yes and that's not necessarily a good thing in all markets. Very low profit margins can result in less innovations and would certainly discourage companies from taking risks (basically by definition)