This has happened in other industries before. Drafting for example when CAD arrived. Entry level wasn't "can draw, willing to learn" anymore, but demanded high domain understanding. So the pathway became compressed learning through study, and field exposure.

Study of senior drafter "red lines": what and why they changed the initial drawing, RFI response etc. Reverse engineering good work. Failed design studies etc.

SWE equivalents: PRs, code review, studying high quality codebases (guess what: LLMs are amazing at helping here), pair programming (learning why what the LLM did was wrong, how to improve it, etc), customer support, debugging prod incidents, studying post mortems etc

We don't hire juniors and throw them boilerplate and tiny bugs while expecting them to learn along the way ad hoc through some pair programming and the occasional deep end. We give them specific tasks and studies that develop their domain understanding and taste, actively support and mentor them, and expect them to drive some LLMs on the side to solve simple issues that still need human eyes on it.