Tariffs raise the price of affected goods allowing local suppliers to grow their business and fill the gap. A lot of countries looking to industrialize will institute tariffs to protect their industry so it can grow enough to compete with foreign companies. In our case it's putting the cart before the horse; our domestic industries are currently unable to supply domestic needs (remember the "logistics" issue at the beginning of COVID?) and several of these goods require specialist knowledge to produce, so it's not like we can just open a couple factories. Which is the other thing- companies might not invest in new factories as these tariffs could go away tomorrow and it takes time for factories to be built and then to even start producing goods. If the tariffs goes away before anything new is ready they will just shut down.