Open source will be perfectly fine if developers are not able to actually make a living spending most of their time on it, this is how this has always worked and nothing needs to change.
People and organizations who want to make a particular improvement to some piece of open source software will. If there are no dollars comming into the front end of the pipe, then those who don't want or need that change, won't make it - and that is perfectly okay. Open source can be quite successful even living off of people writing that code as part of their job or as a hobby. There is no need for it to be a separate career path - if an open source tool can't do X well, then whenever somebody needs or wants or gets paid to do X, that can be committed to that tool by the people whose career involves applying that tool. Sure, extra money helps, but open source communities work reasonably well also without it.
People and organizations who want to make a particular improvement to some piece of open source software will. If there are no dollars comming into the front end of the pipe, then those who don't want or need that change, won't make it - and that is perfectly okay. Open source can be quite successful even living off of people writing that code as part of their job or as a hobby. There is no need for it to be a separate career path - if an open source tool can't do X well, then whenever somebody needs or wants or gets paid to do X, that can be committed to that tool by the people whose career involves applying that tool. Sure, extra money helps, but open source communities work reasonably well also without it.