A scale that would be too massive for people to perceive.

When a game world consists of ten NPC designs, ten trees and ten buildings copied over and over again, people notice that and become bored by the repetition. The world feels fake because we know that reality is much more diverse than what the game is presenting.

But if you could use an equivalent to https://thispersondoesnotexist.com/ to make every NPC and a similar tool for other art assets, that problem would be solved.

In the near future human artists will have to still take the lead as AIs are still too prone to making mistakes, but with every improvement, the AIs would move closer to the point where they wouldn't need somebody to clean up their errors.

We will go from game developers experimenting with AI, to using AI to do the boring work that isn't fun, but necessary. Nobody wants to become a 3d artist to design bars of soap or lamp posts or mailboxes, but if a game calls for a fully explorable house, that is what they must do. AI will take over these tasks so the people can focus on the fun models: the main characters, the guns and the monsters.

From there, AIs would continue to improve, perfecting every task that is presented to them. Eventually they would become equivalent to an entire movie studio, or game development studio unto themselves. There would still be value in creative work made by well known creators, studios or brands, but a growing number of people would be able to choose to just tell the AI what they want, and let the AI create it for them.