>My experience is that that plainly does not work.

The apprenticeship model isn't in practice at any scale in software, I don't see how you could believe that. Practically every career start is self-taught or university to junior positions which is not the high-attention, one-on-one focus you'd get.

>Why invest a lot of money and high-talent attention into someone who might quit?

What happens if you don't and they stick around? You might say 'well, I'd just fire them' but then you are going to have a culture of people always having one foot out the door. And a high amount of position switching in the industry has led us to what we have today where people don't really stay and build for the long-term, and shoddy code bases also drive people to quit.

An apprenticeship model also helps if you can do 3-5 year agreements for training where you see the most benefit from the person in the last 1-2 years.

As good as it has been for my career, switching often probably needs to slow down (while raises go up) and apprenticeships go into effect for better quality training.

All this assuming there isn't another major leap in AI competency though.