Yes and no

I've seen productivity surveys of senior programmers that share the reverse, and that matches our experience. A common finding is that gardening projects are a lot cheaper now when they're just a few extra terminal tabs running in parallel - security, refactoring, more testing, etc. Non-feature backlog items that senior developers value around tech debt are less of a discussion now. They're often essential now: to make AI coding work well, there is an effective automation poverty line around verification, testing, and specification that needs to be reached.

The understanding code thing is tough. Eg, when a non-senior fullstack developer manually edits frontend css code and didn't start from pixel-perfect designs across all form-factors, do they really understand what they did? I wrote the first formal mechanized specification of the CSS standard, and would claim 95%+ of web developers do not understand core CSS layout rules to beginwith: it was a struggle to semantically formalize even a tiny core of the box model as soon as you have floats. If the AI generates live storybooks and in-tool screenshots of all these things as part of the review process, and doing code review "looks good", what's the difference?

I don't truly think this way - my point is to challenge basic claims of manual coding to be good to begin with and whether AI coding is being held to an artificial standard. What I see in commercial and defense software is a joke compared to what we do in the verification world. AI coding automating review iteration fixes in areas like security engineering and test coverage+amplification has been a blessing for quality improvement.

More fundamentally, we require developers by default to be responsible for knowing what the code does and having tested it. Every case of relaxing that rule has to be explicit, eg, clear that something is a prototype, or an area is vibed with what alternate review/test flow, and we are learning as a team what that means in different situations. In practice, our senior ai coders are doing more quality engineering work than the manual coders, both per-pr and in broader gardening contributions.