So, I just researched Atomic Theory and popped into the atomic era. A great artist spawned that turn, and I figured I'd finally get that last painting I need to complete the Hermitage theme. Imagine my surprise when the ability to create a great work was absent. Not even greyed-out. Just gone. Was it being in the atomic age that did it? Thing is, I've built almost every great-works-related wonder plus Eiffel Tower, completed almost every theme set, I've built hotels in those cities. I've gone artifact-hunting. I took the Media Culture tenet and built broadcast towers. I've bent over backwards to make trade routes to as many civ's as possible, and bribed my worst enemies into opening their borders. I got my World Ideology passed, and won the gold cup in the International Games. I can't imagine much else I could have done, and I'm still not on-track for a cultural victory. I guess I'll have to start carpet-bombing with great musicians.