Amateurs are not willing to pay anything for software. Especially not for Linux. Its free. Why paying for?
Mainline is joint effort, a mixture of donations, sponsorship and various business interests. Its done when its done and it remains a big burden keeping it functional. Bill is extreme. Can’t go faster and can’t be paid by one vendor as all other vendor could be paying nothing, benefits the same and kill the one that pay for R&D … mainline is a complex and expensive question.
It is interesting to see how people are happy, unsatisfied and completely ignorant to software development … “I purchase a hardware and it has to work. I don’t care. I expect fully functionality. Fix it. No, I have no interest to pay your time fixing it. You just have to fix it.” and answer to this can not be nice as at least we didn’t sell you anything. Yet.