Collectively, we spend an awful lot of resources on air. Clearly it must be of some value, otherwise we wouldn't bother. Unless it's a scam.
Sure, we're not being metered and charged by volume of air used. But someone, somewhere, is spending money to make sure it's suitable for breathing. And it's a pretty penny too.
Linux is $0.00 per install.
This is like saying you could charge for air.
It's important, but it's already free and abundant. You can't take it back and start charging for it anymore.