Now the Open Source Endowment is a very small organization that starts with ~$5k microgrants. It is not enough for a living but still should help maintainers not only financially but also by allocating attention.
As it grows bigger, the grant size will also grow. One can help with this by donating and bringing in new donors!
I think my point is that grants may not be the way to get what is desired. Most people need predictable, long term income. You can get stuff done with grants, no doubt. But that's not the question - the question is can you build long term sustainable maintainance mechanisms for OSS. I hope you're right and I'm wrong.