I'm skeptical any public company is really going to have the strength to develop junior talent no matter how many experts say its important or what the long term consequences are. ShitCo A will slash headcount and see their stock go up 50%, investors & VCs at ShitCo B will ask why aren't we doing this and will soon follow. The same thing played out with all kinds of manufacturing industry jobs.

The track record in all industries for companies having well thought out plans to develop talent is pretty bad in the age of money. More likely they just fire the juniors, slowly lose seniors and pray for AGI to take over all coding. Maybe it does and they win, maybe it doesn't and they start panic hiring after 5 years.