Essentially I would argue that profit is one of several rewards for risk, not the only one. Moreover in the real world, people invest for many reasons and there are many forms of investment. People may invest (whether financially or in terms of time and effort) because they want to see social value created, not pure profit. They may invest to protect their own futures and so that they can have a greater say in shaping their lives. They may invest as consumers of a service, simply to provide a form of support for the wider aims of the organisation they invest in.
Once this point is recognised, we can see that the problem of market failure lies not with the Share Capital company per se. Rather what counts is who the owners of the Share Capital company are, and indeed what drives them. Acknowledging this fact, led me to set up ESP Projects, a Social Enterprise using the share capital model but which is nevertheless owned jointly by private investors, staff and its third sector customers. FairShares is for me both an extension and a formalisation of this multi-stakeholder approach and I support it wholeheartedly!