"And you never paid for FOSS Linux drivers. "
yes I do! just because i buy amd cards after they openup the spec. 4 years ago i had nvidia cards in my pc.
first action then pay for that. simple they do action i like then i pay for it.
"Nothing in the AMD marketing or technical specifications for the product you purchased claimed anything about Linux support, much less FOSS drivers."
Linux users don't care about marketing linux users only care about hard work. they release spec's and code thats hard work be sure i give a shit about marketing.
"They have limited Linux support for a limited range of distributions on a limited range of GPUs (FireGL on enterprise distros, mainly). Everything else is unsupported, and if it works, that's just a bonus."
we all know that and this means you get what you pay for! means if your card or notebook is not supportet don't buy it like nvidias Optimus notebook crap-