alt Hacker News>How many different models of PCs get released?
If you want to go that route, each manufacturer is responsible for their own drivers for windows, linux, and possibly Mac (though if it’s novel enough, they will do it). Then think about the components that make up a PC. Motherboard, CPU, Memory Control, IO, OS, Audio, Video. Each of those needs to release patches. So its orders of magnitude more than any Android OS. It’s just pure laziness on the hardware manufacturers that don’t want to invest in software/support. They want Google to do that.
The big difference with PC hardware is that the OS will get most driver updates for the individual components directly from the OEM. A driver update for, say, a sound card will directly be available to every machine with that sound card installed. The PC vendor doesn't have to be involved in any way.
It's the other way around with Android. Google does a new core release, and each individual manufacturer is responsible for modifying it for their devices. If you don't bother to upstream your drivers to mainline Linux and use a skin which heavily modifies core Android, backporting those fixes can quickly become a nightmare.