Jack Dorsey has Devs he pays in BTC whose sole job is to contribute to Bitcoin Core development and nothing else [1], they have no affiliation to his companies other than that.
Also, he's an investor in LN labs who are technically their own thing led by Starkbot (Elizabeth Stark) [2].
So, it can and has been done.
Personally speaking, a lot of the 'how would it ever work...' questions that come up here that are thought to be seemingly impossible to solve have often been pilot-tested inside the cryptocurrency space to one degree or another, so if nothing else I hope most of you can find value in that 'us crazy people' are actually pushing the envelope in the edge-cases of innovation.
For example, because many of us have been proponents of UBI (from various source points, mind you) from either a pragmatic or an ideological standpoint, we've tried to see what verifiable widescale UBI deployment (in Iceland) would entail back in 2014; it failed, as many of us expected it would, but we tested hypothesis whose data could ultimately be used later to iterate and improve a system.
1: https://bitcoinist.com/bitcoin-jack-dorsey-square-crypto/
2: https://www.forbes.com/sites/michaeldelcastillo/2020/02/05/j...
Everyone has costs for things like shelter, power, food, water and other necessities, there is a need for some form of income.
I certainly think they should fund projects based on quality, as your reputation for quality increases I would hope that your ability to bring in sponsorship would be higher, though it's also a shame that people need years of their own funding to break in to open source software development properly full time. In many ways, open source development is only for the privileged/rich.
I have no idea how a small developer could ramp this up, but for a larger project, the approach appears to be to form a foundation, and to give contributing companies a chair that's closer to the table.
In fact, from the perspective of the bigco, there seems to be a thriving ecosystems for leftpad-style packages already even without additional money pouring in. Why subsidize it to become even bigger?