"greed"? The force that pushes back on corporate greed should be competition. The problem is the modern trend of consolidation, monopolisation and lack of proper competition.
Why compete when we all own index funds? Just use proxies to communicate and sychronize about "industry and sector costs and margins" and take your share. Maybe work a little on cost reductions to look good, and don't rock the boat: So long as investors can be exposed to whole markets and industries without caring about individual winners, there's really only one owner of the publicly traded participents.
Or is that an exaggeration?