Fair enough. I agree that $500 is a big ask for public domain content, however there is still a service provided by Getty in surfacing this content. It seems fair to charge a fee for that convenience- after all, the consumer has an option to do that work and find it themselves if they value their time less than the cost and have the necessary knowledge. Kevin Kelly identifies this in his excellent article “better than free“ (https://kk.org/thetechnium/better-than-fre/)

Getty asserts a related point in the claim- that the work done to build extensive metadata for the content (which Stability apparently used for training their models) is a valuable service in and of itself.