The aversion to risk of people with limited means is certainly an issue. However, the co-operative movement has now demonstrated that the chance of failure is extremely low. Even if the same incentives don't exist for co-operative entrepreneurs as for capitalist ones, there are still ways to ensure that founders are properly rewarded for theit vision. There still remains, however, the need to create and foster a culture of participation in business management which has been eroded by people's experience of employment. Another theory is underinvestment.
Debt is a low risk investment, typically made by banks.
These banks have not always been confident about co-ops, failing to understand what they are or how their creditworthiness can be assessed fairly. Fortunately, there are today a growing number of co-operative and ethical banks which we can work with. Equity is a higher risk form of investment which gets returns in proportion to the success of the business. This kind of venture capital has usually taken the form of shares with voting rights. Clearly, this is inappropriate for a worker run enterprise, and so it has proved a problem for co-ops to raise.