[toast0]

What I've seen is (more or less) the mainline kernel maintainers for whichever kernel have the objective of making sure the drivers compile.

They can't test what they don't have, and I haven't seen evidence than any open source kernel has a testinfg time with large fleet of hardware for tests. There's more or less an incidental distributed test fleet as users have various testing setups, etc; but driver mistakes in obscure hardware tends to get found late.

It's not unusual for drivers to be found to have been broken for years, and then unless the reporter can fix it, or the fix is obvious from the report, the driver gets removed.

Another path towards driver removal is some interfaces get updated in multiple steps: a new interface is added, drivers are updated to the new interface, the old interface and any drivers that haven't been updated are removed. If nobody has stepped up to update the driver before removal, that's an indication of disuse; sometimes they get added back after removal though.

For the record, Windows isn't necessarily better. I had a printer where there was a working driver, but Windows would prefer the non-working driver from Windows Update, and it was impossible to get that fixed.