I disagree its difficult. When the culture supports mentorship, onboarding and first year experience as high priority items with solid guidelines / process around them, its pretty easy.

but wait, that means changing cultural and such, that's not easy is the response I often get to this, to which I say preemptively:

That I would agree with, because the US business cultural is surprisingly stiff to changing things that would have favorable impact to workers, but that is IMO a different and separate discussion to the fact that this is a readily solvable problem.