It is a double edged sword - the U.S. manufacturers no longer have to compete with potentially better products from overseas, they can push lower quality to the local market for the same price.
This is correct. But this creates an opportunity for other domestic manufacturers to offer a better deal. Look at the Chinese car manufacturers. It was Chinese policy to say basically "sorry, you just have to buy shitty domestic cars or pay massive tariffs." Now their domestic manufacturers have gotten good enough that they are exporters themselves.
