But why would the manufacturer or distributor lower their margins? Charity?
Also market competition can be a factor: if competitors are not raising prices (or by smaller amounts), you might lose market share.
Of course the practical problem with this playing out in increased domestic production is that it's reasonably likely that in 2028 the tariffs will get rolled back, and any company that was depending on them to survive will die. That's a large amount of uncertainty for any industry where there's a significant income investment required to get going.
[1] - https://www.ers.usda.gov/data-products/charts-of-note/chart-...
Not to mention that tariffs on directly imported goods reduce the lowest earners' ability to pay for domestic products.
If the goal was onshoring too benefit the population, it would be coupled with a strong wealth redistribution to the least wealthy to allow them to buy domestic goods. But that's not the goal.
That's not true, even for items which undergo relatively little processing like milk:
1. Cows need feed, and in the US this is mostly corn. This corn is mechanically harvested, shucked, and transported.
2. Cows are milked by machine.
3. This milk is then transported to a larger processing facility where it gets filtered, clarified (fat removal for 2%, skim, etc), pasteurized, homogenized (fat is evenly dispersed), and bottled in a blown plastic jug.
4. After bottling, the milk gets palletized and trucked to grocery distribution centers, which will re-palletize it for shipment to individual stores.
At every step of the way, we use machines that require frequent maintenance and whose supply chains rely extensively on imported parts. On-shoring all of this would be expensive and risky both because Trump flip-flops so often and because our next administration may just reverse the tariffs.
Realistically, what's he gonna do? Shut down the company, which he oh so desperatly wants in the US? Tax them more, driving their cost up more?
Lots of options.
Other ways of reducing value are possible such as reducing quality control effort, reducing quality of inputs, and reducing manufacturing costs in ways that are known to reduce product quality.
Pushing costs to effectively underregulated externalities can also avoid price increases.
It is also sometimes possible to increase efficiency. Even a long term commodity can have potential for efficiency improvements that were considered not worth exploring under stable pricing pressures. (I suspect value reduction is easier and much faster than efficiency improvement.)
Sadly, reducing value can have a disproportionate cost to consumers. Reducing manufacturing costs for a Watchman's boots by 20% may reduce the lifetime of such by 30% and reduce the quality of use by 50% (which may be related to Samuel Vimes' theory: https://en.m.wikipedia.org/wiki/Boots_theory ).