That's not the fundamental cause, though. Companies can't just raise prices to achieve whatever return they want, because once you go above the profit-maximizin

That's not the fundamental cause, though. Companies can't just raise prices to achieve whatever return they want, because once you go above the profit-maximizing price, the fall in demand outweighs additional revenue per item, and once you go above competitor's prices, demand similarly falls. Yes investors look for maximal returns, but those are limited. Fundamentally the ceiling is set by demand and by your competitor's prices.