[nicholasnorris]

The investment schemes do not have to stay static while only the structure of businesses change.

Even if it did, would it not makes sense that investor priorities would change if their only options beyond cooperative businesses were some very small startups and mom & pops?

A system of public banks could handle investment based on the priorities set by all citizens. Everyone would effectively become a shareholder. Successful businesses could be taxed based off what the public invested in those new cooperatives, and those taxes would be used at least partially be used to fund more startups.