Except humans learn from your PR comments and in other interactions with more experienced people, and so inexperienced devs become experienced devs eventually. LLMs are not so trainable.
Some people say we're near the end of pre-training scaling, and RLHF etc is going to be more important in the future. I'm interested in trying out systems like https://github.com/OpenPipe/ART to be able to train agents to work on a particular codebase and learn from my development logs and previous interactions with agents.
If they're unmotivated enough to not get there after four review rounds for a junior-appropriate feature, they're not going to get better. It's a little impolite to say, but if you spend any significant amount of time coaching juniors you'll encounter exactly what I'm talking about.