alt Hacker NewsNo one started photographing paintings and declaring them free to use. If they did the lawsuits would leave a huge impact crater.
Photography started displacing painting as a form of portraiture, but displacing a technique is not the same thing as appropriating the work itself.
I don't see any issues with "appropriating" a work especially if it's not a one to one copy which AI does not produce (without out some pretzel level prompting), especially with regards to visual media (what even is appropriation in this case? Your example of photographers taking images of paintings is not the same as how AI training occurs). In other words, training is and should be free and fair use.