Very few place are still holding onto older equipment because the places still operating cleared the floor space for higher speed higher volume equipment to try and maintain contracts with big purchasers that did or were threatening to leave to get that cheap unregulated foreign production. Turns out that didn't last forever, China isn't letting companies freely pollute anymore nor are they dumping subsidy money into manufacturing businesses to buy new equipment, but they still have all the equipment running, while much of the US equipment was either sold off or sat decaying and unused for decades.

Even if you could prove starting up a US manufacturing business to satisfy these demands was profitable, who is going to put up the investment money? There is no way such a business is going to be able to promise the same kind of returns as investing into tech companies, financial companies, or the overall stock market, and so they continue to mostly not exist. People with the capital to change things are seeking the greatest profit, not mediocre profits, and manufacturing in the US is mediocre profits for all but a few specialized industries.

TL;DR New US manufacturing production and capabilities lacks capital investment because profit margins are not super high and there is basically zero chance of an investment windfall.