But the comment above wasn't about an explicit conspiracy, with billionaires meeting in dark rooms colluding. It was about implicit, uncoordinated conspiracy, where objectives align. My comment is defending the latter
I do think that these limited agreements may be copied by other people in similar contexts, for instance there were other tech firms who made similar agreements with their own competitors. And the big tech anti-poaching agreements may have themselves been copied from similar agreements made in other industries, such as finance and fast food. The illegal conduct probably spread organically through word of mouth, as execs and board members informally exchange this sort of “best practice” with each other.
It’s likely that big shareholders or board members could hold private meetings to advise the CEOs of their companies on how to pull off this sort of trick, if they think it would help the stock price. Given how many people sit on multiple boards, this could be seen as a sort of conspiracy. It’s still very informal and of course it’s nearly impossible to prove.
And, "implicit, uncoordinated conspiracy" is an oxymoron. The word "conspiracy" has a definition.
If all you are saying is "sometimes billionaires are aligned" - sure. Sometimes politicians are aligned. Sometimes teammates are aligned. If one wants a platitude with some predictive power "people are self interested" is going to work more often.