Could you run an economy entirely with mutual and cooperative ventures?

[parochial boy]

This would be ideal imo, but the biggest problem I see with it is that if you are shutting down the option  to invest in equity, then you are effectively shutting off one of the two major ways of generating investment.

Of course, there are plenty of examples of co-ops being succesfully without needing to issue equity to third parties - but on the scale of a whole economy it might be trickier? Maybe you could have a requirement for employees to "buy in" to co-ops (which has a load of it's own problems); or you could obfuscate and claim that mutually owned banks can buy shares because they are mutuals after all; or you just have some sort of government investment bank, or allow non-employee/customer ownership up to a certain percentage or something like that...

At the end of the day, I reckon it could work, but would need need happen at a level above the nation state - otherwise you just get the same old story of the parasite sorry, investor class setting up opaque ownership structures through tax havens that let them bend the rules (and the same old race to the bottom story with regards to regulations and that).