I am no lover of the current system and would love to see it changed to be more equitable. But for better or worse as things stand right now, stock markets and prosperity, even of ordinary people, are apparently very strongly correlated. Ideally fixing them should not plunge the world into recession (or worse).

Where there are inequality issues, surely the safest thing is to just adjust tax rates and social spending to fix those. Viewing securities exchanges as a possibly useful machine that needs watching is much better than turning it into to a gambler's play ground for no good reason.