Isn't the whole point of hiring a junior dev that they will learn and become senior devs eventually?

Your mindset is sadly a decade put of touch. Companies long since shifted to churn mentality. They not only slashed retention perks, they actively expect people to move around every few years. So they don't bother stopping them or counter offering unless they are a truly exceptional person.

> replace "AI" with "junior dev", done.

Damn, that’s a good way of putting it. But I’ll go one further:

replace "AI" with "junior dev who doesn’t like reading documentation or googling how things work so instead confidently types away while guessing the syntax and API so it kind of looks right”

I've been saying it's like an intern who has an incredible breadth of knowledge but very little depth, is excessively over confident in their own abilities given the error rates they commit, and is anxious to the point they'll straight up lie to you rather than admit a mistake.

Currently, they don't learn skills as fast as a motivated intern. A stellar intern can go from no idea to "makes relevant contributions to our product with significant independence and low error rate" (hi Matt if you ever see this) in 3 months. LLMs, to my understanding, take significantly more attention from super smart people working long hours and an army of mechanical Turks, but won't be able to independently implement a feature and will still have a higher error rate in the same 3 months.

It's still super impressive what LLMs can do, but that same intern is going to keep growing at that faster rate in skills and competency as they go from jr->mid->sr. Sure the intern won't have as large of a competency pool, and takes longer to respond to any given question, but the scope of what they can implement is so much greater.