That's bunk. The OP is literally "feel[s] the need to hire junior" engineers because he can ChatGPT that work. How are they going to learn a job they won't be given the opportunity to have much faster?
> If GPTx ends up in the narrow area where it's universally smarter than junior engs but definitely not capable of being a senior eng, then junior engs will just shift to the little remaining work for senior engs, shadow them for months to years like an apprenticeship.
That doesn't make much sense. That kind of apprenticeship would be pure charity, so it's not going to happen. No one is going to learn to be a senior engineer in "months," and no one (except someone's rich parents) is going to pay for someone to sit around unproductively in and office for years while they learn. Even interns are required to produce output that adds value. They do that by successfully completing junior-level tasks that need to be done well.