There is hardly scarcity in art now, though. Not as a whole. If you like a particular style, you can usually find it at an affordable price so long as you aren't going by "famous" or "brand name".

I'll also add that scarcity will be simply built-in. Most folks won't initiate such art - and such art has to be initiated. There will still be a personal selection process going on with a human behind the scenes. Just because the computer can make so many doesn't mean we'll see that many at all. I imagine it will eventually edge out some art forms: Making advertising graphics for movies and print, for example. Making logos. And so on.