The ultra-wealthy deploy or deny capital to mold the society to their views.
"Social utility" is just this mind virus the ultra-wealthy spread in everyone's mind to make their rule-by-proxy feudalism palatable to the peasant class.
but to your point, you are exactly correct. Stock markets is a game, designed to methodically transfer wealth from the peasant pockets to the ultra-wealthy that write the rules of the game.
One, and most common, game is to have peasants as suckers of the last resort and have their pension funds buy all kinds of garbage because "mandates". Why would anyone want to hold negative yielding debt? But they do.
What the fuck are you talking about? If the stock market didn't exist, it would literally be impossible for average people to own (parts of) extremely productive and profitable large companies.
The average Joe would just fall even further behind.