Well the people will still need that things that were imported, eventually you’ll have to have an industry to cover that need. Picture this just an extreme case. All clothes are made abroad, imagine the tariff makes it “unbuyables”. The people will still have the need for clothes so that creates the space for someone to start making clothes and sell them eventually making a textile industry.
Now the problem is this could take years the internal industry could be shit and a myriad of other problems that will surely will affect the poorest people the most. Economics explained has a good video on it you should check it.