Its just end users also need to organize to fund and promote open source. There is a perception these things are taken care of but they are not, most Linux groups are industry bodies.
If Github benefits from Redis and its just one of hundreds of examples then there is a moral case to be made to support it and give back to open source in someway so the stream continues to flow. In this case Github had not even bothered to reach out to the Redis author, so there is something wrong here in how successful startups are engaging and using open source.
Approval of prize proposals and recognition of the correct wallet address of winners can be handle via stakeholder voting among existing currency holders. The currency base can be bootstrapped by recognizing the efforts of volunteer developers who would otherwise be performing work for free.
If an API is then added for transferring and proving ownership of shares, developers will then be able to sell their shares in independent exchange markets for other currencies if there ends up being a demand. Third parties might be interested in buying currency from developers in exchange for cash so they can list prize proposals on the network for completing work on software that benefits them.
This would potentially allow the foundation to indirectly compensate developers without having to raise the funds and hold the cash itself.