> it can just impose tariffs on imports to do so
This is how you grow a sclerotic, internationally-uncompetitive domestic industry. See: shipbuilding.
Where tariffs work is as a nursery policy. Give firms a safe haven to grow in. Then let competition hone them. South Korea has pioneered this playbook; China copied it. We were sort of doing it, but the current administration blew up our nascent new energy industry.
> the current administration blew up our nascent new energy industry.
Which industry is that?
It's also debatable how important tariffs even are for "infant industries". In most situations, if you ever remove the tariffs, the native industry is just as likely if not more likely to die out to any serious foreign competition.
For South Korea and China, tariffs were not a very key part of their industrial policy. Which is not to say that the government didn't have a massive hand in the success of their native industries. Case in point: shipbuilding for South Korea. The government was key in securing the capital investment in the massive drydocks the entire world depends on.