I don't agree with you. The way you put it is more or less like this:
"Stallman claims you mustn't write proprietary software, but nobody really
knows how to make it work in practice".
Free software development isn't really a niche. RMS claims that the most of
the software that is developed is free, and I can confirm this from my
experience. The software I wrote while doing it professionally was free and
so were all of the programs written in my company (they weren't copylefted,
but they were still free). And, surprisingly, we all got paid for our job.
Don't get tricked into thinking of the free software as of a unicorn of the
software land. It's here, and it's doing great!
