I've seen this at work. Giving Claude Code to a mediocre programmer gets you mediocre results. The really effective engineers with coding agent can accomplish a lot. Thousand monkeys...
...And then they train their next generation models with these elite engineers' skills.
I've also seen this. But I'll extend it to saying that giving Claude to a bad programmer gives bad results.
And seeing how people use it: good programmers review output and iterate to get better output. But bad programmers simply trust the output is good: they have no ability to review it themselves and often don't try.