They're currently still at the "create a million branches until the tests pass" phase. Once they are more capable of genuine design, refactoring, and maintenance, their code will arguably be more readable than code written by humans, as they'll be more able and more inclined to refactor on the fly, rather than letting things bitrot the way we do. They'll be better able to refactor without regressions, refactor across services, all without disrupting feature development and parallel work (because they're fast enough that work will become more serialized), and remembering to update documentation accordingly.

Unless there's a wall getting AI to plan, design, and refactor better than it does now.