I think there's just too many confounding variables to say. ZIRP policy ended in 2022, with interest rates going up 5% between 2022 and mid-2023[1]. This both means that money was historically cheap when these early-career developers were being hired in the peak, and it was relatively (in terms of the past couple of decades; eg, the modern tech industry) expensive after.
We've seen layoffs as a result of this, and nobody's hiring a cohort of juniors when they're trying to afford the employees they already have.
On top of that, companies are firing the money cannon at AI initiatives and experiments (some of which will be successful and others which won't), leaving less money for humans.
Anyway, it's just a single occurrence of a hiring drop in a single economic cycle. Unfortunately, it just happens to perfectly line up with the rise of GenAI. We may never be able to tease apart cause and effect in this period, and we certainly won't be able to do so until we have at least a handful more years of data to see how junior hiring does or does not rebound.