From what I have read this isn't opening a new studio, this is purchasing an existing one that will work on porting BG3 to the Switch or whatever Nintendo console. Starting work now is a smart investment, especially if they are concerned about the revenue stream being able to support long term development. Although Nintendo doesn't allow EA games so they won't see profit until they have a finished product, but obviously it helps to have a studio whose work they trust.
So no onboarding, no getting people up to speed. This actually offloads a lot of work to specialists who can likely do it a lot faster.
