Perhaps. Now what about OpenBSD and NetBSD, or whatever else? If they provide specs then they don't have to write drivers, but they don't get to bless or withhold their blessing.
There was a stink a while back where Adaptec had been providing drivers for FreeBSD, but then stopped. People were stuck either not upgrading their boxes (bad!) or moving off their RAID setup (painful, expensive!). It's ugly. With specs, there is not this issue.
The (pervasive) idea that vendors providing drivers for your system of choice, for the time being is being open source friendly is something the vendor promotes, but it's not actually friendly.
