Actually I would think GPUs are one of the biggest counterexamples where driver support has been noticeably improving recently (mostly thanks to Valve and Steam

Actually I would think GPUs are one of the biggest counterexamples where driver support has been noticeably improving recently (mostly thanks to Valve and Steam). Even the open source drivers work well enough to let you get work done (although the performance might not be where you want it to be). Compare that to driver support for things like the fingerprint reader in a Lenovo Thinkpad. I wouldn't want to bet on getting that working at all, unless Lenovo had preinstalled Linux for you. And unlike GPUs, this is likely to be all or nothing, so if you don't get the drivers you can't use that hardware feature at all.