I think people will still find joy in it, just of a different sort. As an analogy, used to be that you had to program a computer with assembly language, and it was rather painstaking to do. There were some real wizards doing that sort of work, like in the Story of Mel. Nowadays though, we've got high-level languages with compilers that do all the grunt work of actually writing assembly for you. Some people still worry about assembly specifically, but the vast majority of programmers don't. The joy is no longer in writing the absolute fastest bare metal assembly you can for most people, it's in using the right algorithms to solve a problem. You can write a few lines in Python that would've taken someone weeks to write in assembly.

Something relevant to note in the above is that smarter compilers eliminating the need for people to write assembly directly didn't mean the end of programming as a profession. There's been an explosion in programming jobs, exactly because each person can do so much more than they ever could before, opening up new possibilities that weren't there with everyone writing assembly.

Likewise, I suspect the scale will change here. I admit I'm not an artist, but wouldn't it be cool to see your artistic vision across an entire game? You could create an entire virtual living breathing city on your own without having an army of artists working on the grunt work like the exact concrete texture. If you decide to tweak the feel of the art, you don't have to spend weeks redoing all the grunt work. Alternatively, if you draw a landscape that you get just right, imagine being able to experience it by having the AI generate a virtual world for you to walk through based on it.