I can get a dev perspective on the topic even though I’m not a game dev. Each game is going to have someone in charge who is balancing stake holder feedback, developer concerns, and vision. Something like photo realism is going to be really hard to get through. It’s expensive and time consuming which will make a lot of stake holders say no. It’s difficult if not impossible for developers to do it with other requirements (like how well it runs on certain PCs, consoles supported, or delivery schedules), and then that has to be the idea from the start (or vision). It’s really the most stringent decision for all three. More than likely the project doesn’t go perfect so it’s the first thing to go.