GNU/Linux is already supported without a (single) megacorp. So not all OSes have this problem.
Sailfish is more like GNU/Linux, that is the OS in this context. For Jolla that is less code to maintain themselves then what Google maintains in Android/Linux. Hard forking Android/Linux looks to be quite a big bite to chew on.
When millions of dollars support a feature, that feature beats others- even technically superior ones, on the basis of support and polish.
We’re all playing to the tune of what Google wants because Google has the power.
Imagine a world where theres no Linux because MacOS and Windows paid lip service to people using partially functional derivatives of their OS’s, they’d still push things like liquid ass and windows recall, and those features would be spidered in.
Then people would be saying “don’t use linux, you can just use WinCore” Even though using Wincore is aiding Windows commercial interests over those of the industry as a whole.