RMS' heart is mostly in the right place, but he's a fanatic who is 100% out of touch with the real world.
The same way anyone who think selling metamphetamines to vulnerable people and kids is unethical and wrong, then you should not do it and find another income to feed your family.
Nobody is put a gun to the temple and forced to write proprietary software to make a living. There are myriads of other jobs.
For most part of his life he was living in his office at the university, technically homeless. After that period he lived in a home designated by MIT, possible because they got tired of the building code violation of having a professor living in his office.
I understand he's forgone the amount of wealth he could have accumulated by just working in the software industry in the name of his cause, and that is laudable. However he thinks everyone should do this despite the greater burden they'd have to shoulder. All the people he tells shouldn't be making non free software so they can support themselves and their families are not going to be given free lodging by MIT.
However your comment above said he lived comfortably off the income of his own celebrity. We would have to twist the word income here for a bit to cover this kind of situation. The comfortably part is also a bit questionable, but I guess living at the office can be comfortable to some people. The description just didn't fit the situation that well, which is why I wrote the above comment.
Yes, by working on unfree software, an occupation which he uncompromisingly condemns. Programmers working exclusively on free software would be earning much, much less on average.
You mentioned exclusively, that's true that you might have to write custom, closed code for customers at many of those companies. But that's still better than exclusively working on non free software.
All of the open source companies/people that come to mind are not selling libre software, they are all selling some kind of service - support contracts, managed hosting, etc - or they embraced some kind of freemium/"open core" model (so they are really selling non-free software), or they are funded by charitable donations and sometimes public grants, often by having some large non-free companies being sponsors (Linus Torvalds is paid this way for example, through sponsorship money from the who-is-who of the non-free corporate world distributed through the Linux Foundation).
It doesn't sound complicated to me to understand that you can sell games whose code is open source but the 3d models, graphics, levels building and artwork aren't. Customer would still retain all free software liberties, be able to port the game to other platforms and the dev studios would still get paid.
So yes, although your observations are not wrong, they do not apply universally.
> Nevertheless, more than 6000 of these individuals choose to help fund the project to the tune of between $150k and $210k a year.
How is this not covered by the posters comment about it not being a business but a charity if you rely on people paying more than they need to?
If that's your definition, then sure.
That's not my definition.