The thing I like this 'minimum wage' approach is that it fills a gap in traditional funding models, where ordinarily you have to prove to someone else - maybe a government bureaucrat, maybe a tenured professor, maybe Y Combinator, maybe randos on KickStarter, depending - that your idea is a good one. And if your idea doesn't involve making a profit or publishing a peer-reviewed academic paper whilst earning a PhD, most of your options disappear.
But often people with good ideas (as well as bad ideas, mind you) believe in something a lot but they don't know how to articulate the idea to others. So I would propose that if you've got an idea, you should be able to work on it, at least for some period of time, without first proving its merits in a grant application. You need only prove, somehow, that you are doing work and not playing video games or whatever.
It would probably work best if there is some minimum experience level (e.g. Master's degree or 2 years industry experience) so that the worker isn't clueless, and a sort of coach or mentor who is paid at market rate to facilitate - to make sure each worker is aware of prior art to avoid duplication, to connect workers with each other if they could logically work together, to provide moral support... and the fact that the pay is low should discourage participation of 'normal' people, who will invariably choose to work in industry instead. This is good - I don't expect much from normal people, and low pay implies more workers can share the same pile of cash.
But there's no way I can get Musk to read this. P.S. there's little reason to restrict the fund to software developers, but hardware engineers, chemists etc. presumably need extra money for equipment.