I don't package any of the software I write for Debian because I don't want to have to jump through their hoops. I don't blame device manufacturers for wanting to avoid jumping through Linux's hoops. Especially with having to deal with Linus.
Nobody likes Apple's app review process do they? I don't think device driver writers should have to go through that.
(I also wish they would open the code but not having a stable driver ABI clearly doesn't make that happen.)
I think a valid reason for not having a stable driver ABI is that it's a mountain of work and makes everything else more difficult. But I've never heard anyone give that as the reason.