So if SM enables GPU rendering will they be limiting Cycles to NVidia video cards as well?  Making 3 render engines a lot of folks can't use........not seeing much business sense in that.

i dunno, really, honestly do not know.  what i can say, about myself, is that if i go to a buffet style restaurant, i'm tasting [yes, i'm still hungry, dammit] a little bit of everything because how else do i know what i might like/dislike.  i can also say about myself that i like options... esp. when i'm hungry, be it food, creative endeavours, etc.

As should we all - have options.  Which has been my point all along...........giving people options! Another render engine, PBR or not, that requires specific hardware and specific computers, LIMITS the options available.