This is what people don't seem to get. I'm pretty sure a large proportion of Titan sales were for GPU rendering & other productivity uses : Believe me, in those circles its talked about very highly since day 1. With GPU rendering, all the meshes & textures have to fit into the GDRAM of the Graphics card - the 6GB of the Titan wasn't some vanity luxury thing - it allowed people to render sets & scenes twice as big (in data terms).
A PC with a moderate CPU & 4 Titans with a huge PSU is the standard render-node configuration for Octane render pipelines for example. Granted, this is only a small corner of the Cg rendering market.
Titan wasn't just a halfway between a tesla & GeForce in architecture, it was a halfway in terms of features & user-base too. It never made sense as gaming card in financial terms, although I'm sure that lots of the bling brigade bought them anyway, their call I guess.