Tiny part? Your immediate preceding sentence observes that the large pool of kernel contributors live on salaries provided to them by Fortune 500 companies.
Is that a roundabout way of admitting that you're wrong and open source can be sustainable?
Not even close, because those developers are employees from Fortune 500 companies in one way or the other, they are not being paid by other developers paying to use Linux based software as such.
I don't understand. "Not even close to sustainable", you say, then complete the sentence by describing the situation in which Linux has been and continues to be sustainable.
What is the relevance of that part? Your claim that open source projects can't be sustainable is straightforwardly false, regardless of whether there are any Linux developers who are payed by other developers in order to use Linux-based software.
Similarly, your claim that "open source folks" don't value open source software as worth paying for is straightforwardly false, regardless of whether they pay out of their personal bank accounts or push their Fortune 500 employers to donate money and time (which every Fortune 500 calculates in terms of money).
Is that a roundabout way of admitting that you're wrong and open source can be sustainable?