This is a great idea. Opensource the driver and they will definitely sell a bunch.
But are they making a bunch of money on them? If not (i.e. they being sold essentially at cost) there is no (real) advantage for OBi to invest the support effort to do so. Development and support costs money. Some individuals may do it for the fun (or the challenge) of it, but corporations are responsible for looking at the long term return. What would you pay for a license for support of each device in Asterisk? And how many of the "bunch" of people can you actually get to sign on the dotted line for that license? If you can show a real number, with real payment info, I am sure OBi would consider the ROI.