I don't see this doing much unless everyone stops at about the same time. The largest shareholders have a disproportionate amount of power to influence the direction of most companies.
For much of SP500, the largest shareholders are the passive investors. It's common that an activist hedge fund can influence decisions with a mere 3% or so stake because the likes of BlackRock and Vanguard support them or abstain.
If you properly punish the shareholders, then it doesn't matter if they stop or don't. If they stop, the bad behaviour stops; if they continue, the onerous penalties continue. Anybody who wants to sponsor bad behaviour with their AUM can pay the appropriate fee.
