Earlier quoted context omitted.
The difference being that you can install or upgrade Windows on a system without buying a new laptop or requiring support from the vendor; the vendor doesn't lock down laptops to prevent upgrades and force people to buy a new device instead.
Which is mostly a problem that Google themselves architected into Android. By not building a sensible HAL in to android like requiring ACPI in the hardware for the first android phones (especially the moto droid which they worked on closely with Motorola), they condemned us all to vendors-specific kernels and bootloaders. Google's inept 'management' of the android ecosystem has left us with openness for hardware vend…
By the way, the upstream Linux kernel supports the Nexus 5X! http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.9...
And the bootloaders are based on fastboot pretty much everywhere I think? At least that was the case with the non-Google-related HTC phone I've had.