Boards are low tech and low profit, does American company and workers even want to do it?
What this administration is doing is not a recipe for success: trade wars with everyone, immigration crackdowns, and unpredictable tariff policy.
EDIT: Oh and hinting at invasion (Greenland, Canada) doesn't help either
But Taiwan or the rest of Asia is still a problem given the tensions in the area. If China did something it could seriously effect supply even if it wasn’t an attack on whichever country was supplying us.
We need friends making things in Canada or the rest of the Americas or Europe or Africa or some other place that isn’t China or directly under their thumb.
Even without action by man. The wrong tsunami or whatever could effectively wipe enough out everyone would be screwed.
We need geographical diversity too. The existing alliances we’re burning to the ground don’t solve that.
'Most all of which falls square into your "low tech and low profit", from a right-thinking* American company's PoV.
Not to say that a saintly American company could do much better, if it tried to swim uphill against America's vastly-higher cost of living (vs. the countries where most of that stuff's manufactured). And other problems beyond its control.
*profit-obsessed, generally
Even if it was just motherboards in particular and not others, that seems like a necessary step in securing the supply chain and if we only do that for national defense the benefits of competition likely won't extend to consumers that are still exposed to trade taxation.