I think the interesting test case would be to take an established franchise (Baldur's Gate, KOTOR, Deus Ex), and make a complex, hardcore PC-only game using that franchise.
I say this because I wonder if part of the reason for the PC flops is that they were unfamiliar subjects (Planescape? I remember looking at the box and scratching my head, not knowing what it was. Only after reading glowing reviews did I take a risk).
If a speculative Baldur's Gate 3 - a game using a very established "hook", but made with a plot and dialogue as rich as Planescape: Torment - bombed badly in the marketplace, I think we'd have to concede that the hardcore audience is just too small to support our passion.
Thoughts?
Istari