Earlier quoted context omitted.
The "guy in a bathrobe" is still the lead and has the final say. Is he compensated anywhere near what Mozilla's CEO is? In fact is the total comp of all the people significantly involved in Linux kernel development anywhere near the total comp of Mozilla's C-suite? I doubt it.
You're now making a tangential argument about whether people are being paid their worth and frankly that's never been the case. Most of us developers, devops and sysadmins are paid an obscene wage compared to many critical services like nursing. Is it fair? Probably not. But that doesn't have any baring on the complexity of Linux vs Firefox.
However, you can compare the people in the same business, such as those writing software for operating systems and web browsers and compare the cost and productivity in both.