In the past, countries would put tariffs on importing cars, but not on importing car parts (with some complex definition of what constitutes a car and a car part. IIRC, there once was a loophole where one imported a car and converted it into a van by removing back seats to avoid a tax on importing vans)
Nobody is building a new factory, based on tariffs that they expect to be gone in three years time.
For many industries it might not make sense unless it's a 5-10 years long plan, the risk of investing a lot to build a new factory, bringing it online over the next 2-3 years, to then have tariffs removed and making your new shiny factory more expensive to run than one outside of the country, will also be factored into the total cost.
The tariffs are so broadly applied that the risk factor is much more massive than anything the USA experienced before (like during the Japanese cars era of the 70s/80s), it's wishful thinking the domino effect will happen in the short/medium-term.
If costs goes up then either prices go up too or margins go down or a mix of both.
Your second sentence indicates the more significant problem though, because that uncertainty on timelines makes even the 3-4 year time horizon questionable. Nobody is going to invest anything based on tariffs that may go away or change next week and the only way you can tell if they're sticking around is waiting so long you don't have time to make the investment any more.
It might be different if Trump came in with a clear, transparent tariff plan on day one. But they're already all over the place and being implemented in extremely unpredictable ways. Some people might argue his unpredictability is an asset in general, but it's absolutely not in this case.
They won't be competitive prices though; they'll have to charge more because of the capital costs in setting up a whole new factory and supply chains, increased labour costs, and having to pay tariffs on importing parts.
I imagine that not being able to export cars from this factory due to reciprocal tarrifs will also drive up prices, due to things like lost flexibility, redundancy, and economies of scale.
This also means higher prices across the board for consumer goods, but the worker still net benefits greatly.
Who does not benefit: The people who do not work. And that's fine. But it's also this class of people who make the entire political and media class, and hacker class apparently, so that's why we have this enormous resistance.
"Domestic production will replace imports" is conditioned on the cost of domestic production being lower than the cost of imports with the tariffs added. "Just spin up new factories with capital investment, raise wages substantially to get people to change careers from service industries, and train all these new people" isn't going to be a cheaper approach to building furniture than continuing to import it from Vietnam with a high tariff.
The effect will be minimal new domestic manufacturing and higher prices for large numbers of goods.
And low paid workers in the service sector aren't low skilled and costly to get going. They're intelligent and honest, and would be fine workers in manufacturing if given the opportunity. They're working in the service sector because those jobs couldn't be off-shored.
But the second scenario is a massive investment. It not only requires the economics of it to work today, it requires knowing what the situation is 1 or 2 decades down the line. You can't build a car factory in two years. Barely in four. And even if you do, it doesn't matter if it's likely to operate at a loss in 8 years!
The most important thing for that type of investment is stability and predictability, not just "the costs will be lower for at least 2 years now! or maybe 2weeks we don't know since the tariffs seem to come and go depending on which side of bed the local czar wakes up on".
Corp one has two factories one smaller one in the us one bigger one in the eu. They will now shift more of the production to the us from eu to avoid tariffs.
Corp two only has a factory in the eu. They will now build another factory in the us to be able to avoid tariffs and keep selling their goods at competitive prices.