The article says there wasn't a pipeline, and then describes a process by which junior engineers became senior engineers. That's a pipeline.

It doesn't have to be incredibly standardised and gamified to work.

Are you telling me juniors aren’t facing hard problems anymore? I doubt that’s the case. They’re probably banging their heads against the wall trying to understand why this or that doesn’t work… just as they always had before. AI isn’t a magical wand that makes everything just “work”. Probably never will be.