You're thinking about it on a too small scale, but there are many more factors - it's not just a single transaction! Consider what happens to stocks when a company does something unpopular.
I reiterate my recommendation of Ludwig von Mises. His books are really good and it's worth a read even if you completely disagree (just like I read Marx). He tried to answer every question you've written here and definitely more in detail and better than I ever could. There are even individual texts online (taken out of his books) where you can read about a single issue - the texts are not even that long, 20 minutes a piece.
>You're thinking about it on a too small scale, but there are many more factors - it's not just a single transaction! Consider what happens to stocks when a company does something unpopular.
Their success might not depend on popular demand or any stock market. They might have control over something valuable like oil or water supplies, which is not very elastic in its demand.
A company's success always relies on customers; the key here being elasticity in supply because then customers can simply sidestep the offending company by creating a new one. Of course the company might somehow gain a natural monopoly, however I think that technological progress will solve that for us - there is a lot of water in space and oil will be replaced by electricity/hydrogen pretty soon anyways, definitely earlier than any entity at all including governments would be able to control even a single resource planet-wide.
Then there is the people factor - people are not dumb, they simply will not sell their water/oil resources if they see someone trying to build a monopoly.
IMHO oil company influence on the government is a major hold up of electrification (actively opposing nuclear power plants and so on) - without that influence electricity could be much cheaper and electric vehicles in bigger demand, government funds could be invested in research of batteries etc.
The assumption of modern anarchists is that contrary to the past, a single individual today is very powerful and independent thanks to technology and the riches it comes with - and they could use that strength in combination with other individuals to resist corporations and shape the world around them. Consider that just 100 years ago mere communication between ordinary people was almost impossible on longer distances, today ordinary people are able to buy a tank or a small fighter jet (of course in a group - BTW I actually have a friend that owns a tank and another friend that owns a fighter jet, of course gunless).
I reiterate my recommendation of Ludwig von Mises. His books are really good and it's worth a read even if you completely disagree (just like I read Marx). He tried to answer every question you've written here and definitely more in detail and better than I ever could. There are even individual texts online (taken out of his books) where you can read about a single issue - the texts are not even that long, 20 minutes a piece.