Ah, the 'ol "workforce greening" where we get rid of all the expensive old farts and replace them with younger/smarter/cheaper devs right out of school.

It's brilliant and it always works. There are no downsides whatsoever.

What if it includes them? Doesn't seem like that would change anything.

they could also be stuck under the manager of managers with no upward mobility.

Significant amount != all

And which ones do we keep? Which senior engineers are just coasting and which are among the few who are the final reservoir of institutional knowledge holding everything together?

Does anyone know? Meh, let's just hand the task to HR and hope it all works out.

Ah, so "everyone but me" type deal.