What if vendors released the source code for the hardware drivers after the devices fall out of official support? Even if nobody at the company has time to support the hardware there is always a chance that the community can take over.

This is how Linux maintains driver support for hardware long past the point where it doesn't work on modern Windows or MacOS. I've noticed several occasions where the support stops because the kernel was updated and nobody wants to make the effort to port the drivers forward, especially since those drivers were delivered as a binary blob.