StackOverflow as built back in the days of Web 2.0 where the idea was that user generated content formed in the days of the (relatively) altruistic web.

There isn't any clean way to do "contributor gets paid" without adding in an entire mess of "ok, where is the money coming from? Paywalls? Advertising? Subscriptions?" and then also get into the mess of international money transfers (how do you pay someone in Iran from the US?)

And then add in the "ok, now the company is holding payment information of everyone(?) ..." and data breaches and account hacking is now so much more of an issue.

Once you add money to it, the financial inceptives and gamification collide to make it simply awful.