You do, actually. Countries that have succeeded with tariffs to "build an industry" eventually forced their companies to compete in the foreign market (look at Japan and South Korea) so that they would not be fake leaders.

These markets produced actually competitive businesses that thrived and outcompeted the market leaders (US and European companies) in multiple industries. So if you keep tariffs forever you end up with Russia or some other backwater where people are forced to buy shitty goods because you have no access to external markets.

The computer market in Brazil, for instance, was like that. Most of what we had were pirated hardware, because there was never an effort to create a real industry in the country, they would just copy and paste whatever was available out there and "launch" in the local market, so even with years of tariffs and protectionism the country did not produce any player in the computer manufacturing market.