As it turns out, no one wants to invest in infrastructure when all the inputs are going to be tariffed to oblivion. All else equal why invest in USA when you could invest somewhere where you can import the needed inputs much cheaper? Protectionism isn't enough to overcome losing access to world markets.

Eventually the protected industries will be totally disconnected from global markets causing them to lose global competitiveness, to the point they cannot even compete with the black market markups. And then you are maga, er mega, fucked.