I'm not a professional artist or marketer, but I suspect the main reason we see the pursuit of realism in games is that it's easy to communicate and coordinate,

I'm not a professional artist or marketer, but I suspect the main reason we see the pursuit of realism in games is that it's easy to communicate and coordinate, so it reduces uncertainty across the board. Developing a style is hard and requires a lot of coordination across different teams to understand and internalize what approximations are being made where. At scale with hundreds of artists, it becomes very difficult. If, instead, the approximations are enforced by the tech and the goal the artists need to consider is just to create something realistic, then that's easy to get started with without needing a concept artist to dictate everything. There's probably a crossover point of team size where realism has lower risk and lower cost. In practice, I think what we see is that the more creatively-minded large studios shoot for 90% of assets being "realistic" with some strong stylistic choices for the last 10% that really defines the look. On the marketing side, there's something to be said for knowing that your visual style will be uncontroversial for the most critical time period for getting sales (launch). Looking horrible 10 years from now doesn't really matter if you're trying to recoup your investment today. It has slowed down now because a lot of the low hanging fruit has been done, but a decade or so ago, graphical features were one more reason marketing could point to for someone to buy a game. Some people really do buy games because they look pretty. Even today, there are games notable only for being benchmarks.