But that is very different, every company owned by shareholders starts behaving in exactly the same predictable manner. However as long as the founders controls everything the company behaves as the founder wishes, it could be good or even worse than what you'd get with shareholders. On average it is probably the same but for an individual company it still matters a lot.

Yes, but they are not subject to the whims of short-term "investors" who only care about maximizing the next quarter or financial year's numbers.

That's the biggest problem in modern public corporations, a significant number of shareholders have no long term interest and will happily hurt the company to sell out with a higher number.

I hold no delusions that Valve is doing things for my benefit, but they have managed to position themselves in a place where their interests and the interests of PC gamers mostly align.