Unless something weird is happening the PC will remain relevant because that's also the system people are developing games on. Despite that the game will eventually only run on a console. Where the problem is, specially in relation to artists, is that if the studios do not provide dev tools for their games, they will have a more difficult job to find trained artists (specially LDs). Because it doesn't help much if you can create nice things in 3dsmax or maya if you can't create something that will run on the console the studio is targetting.
Anyway, I think that in the future you'll see console games with dev tools that can be used on the PC (probably only for the PS3 because the rest is closed for consumers). For example. Imagine there is no UT3 for PC. The UT3 for PS3 disk would contain unrealed. You simply "install" unrealed and the assets on the PC (directly from the bluray disk), develop your levels in unrealed, and do some "PIE" testing. Then export the stuff to be play tested on the PS3.