I understand the idea as "provide what is necessary for someone to reuse the hardware". Just the bare minimum, like how to flash a firmware and a minimal firmware.

Now for many products, nobody would spend the time needed to make it actually work, but for some it may be nice.

But I agree that it is more complicated than it seems, and realistically that would be on a case by case basis.

Honestly between the ability to flash firmware, interface specs, and maybe PCB schematics that should be enough to use an old device for a motivated individual.

My personal pet example of this is old cameras, lenses, and digital backs. Plenty of great hardware out there that currently requires very extensive reverse engineering to use that would be made a lot easier with firmware & schematics.