[pythonaut_16]

I'm not talking about personal risk, I'm talking about risk of loss in absolute value, i.e. the investor is risking more capital so they claim a bigger share of the reward.

If the musician was able to provide enough capital/resources on their own by risking their entire livelihood they'd have no need for an investor and could take the entire profits of the venture for themselves.

I'm not making a moral judgement here, I'm just saying that it's a fairly straight forward logic as to why people who "only contributed financing get a bigger cut". The OP is wrong to claim they get a bigger cut because they're already rich, they get a bigger cut because they're risking more capital in the venture. It is secondary that them being rich means they have more capital available to take risks.