How long does it take for institutional knowledge to fade? If we need the Army to provide us tanks will we need advisors along with it?

How long does it take for institutional knowledge to fade?

When tank battalions were disbanded we were told its no problem because the Army could provide them.

Fair enough but will they also have to provide advisors?  Will we need our Battalion Commanders to get a quick and dirty from the Tank Company Commander on how to employ his force?

Is the Marine Corps continuing to keep up to date as the Army's Armor evolves?

Its just not tanks either.  Assault Breacher Vehicles are gone.  So is bridging equipment.  Quite honestly combat engineers in the "legacy" version of things is no longer part of the Corps.  Breaching fortifications/minefields, getting formations across rivers is out.  Going thru a wall?  All about that shit!

I get it that "assaults" are no longer part of the mission set but what happens if the Marines are called on to conduct one? Will it by necessity become a case where the Commandant says "we can't do that" and "you better call the Army"?