Re: Yes but evil Steve has declared...
Absolutely a small market - that is why they currently pay a lot of money to anyone catering to them, and why Apple haven't bothered selling 'artist's tablets' to them. It is a smaller subset of the small market that kept Apple alive during the '90s.
Adobe are actively working in this area, though, promoting a stylus and ruler combination for vanilla iPads.
Still, SoC and screen prices fall year on year - even if digitiser tech doesn't - so it might get to the point where a digitiser becomes a good way of differentiating a product for not too much extra cost.