If you think foreign competition was a major factor, the responsible parties are the executives and engineers of the Detroit automakers, for being worse at their jobs than their Japanese and German counterparts.
Those executives may have done a great job, improving the quality of their cars to the point that they can sell as many as they do today, in a wider competitive environment.
In the US, down about 25% since 1976, actually. This reflects cars lasting longer.
[1] https://www.advisorperspectives.com/dshort/updates/2016/12/0...
So, all things being equal ...
A mercantilist or protectionist would jump straight to "Americans drive worse cars."
So there is a policy choice: under free trade, Americans get to drive cute Beetles and sporty little Civics, instead of giant Pontiac boats. Under protectionism (assuming version 1), Detroit remains a city, not a bandit-infested wilderness.
Human beings (the Guardian would call them "neoliberals") made this choice. So, they're responsible. This does not constitute an apology for the '72 El Camino.
How do you decide what to freeze, and how do you decide which year to freeze it in?
I could argue we had a similar moral imperative to prevent the destruction of the livelihoods of horse-drawn carriage drivers. What if you had made this argument successfully in 1890 and the auto industry was never allowed to exist in the first place? Would you acknowledge the same responsibility for the nonexistence of Detroit that you assign to free trade now?
Yes, I'm aware that this makes me a nutball -- some kind of communist or fascist or something. I used to be a libertarian, if that makes you feel better.
If horses were citizens, I'd definitely preserve the carriages. They're not, and the carriage drivers could become chauffeurs. Not that there was a plan, but that would have been a fine plan.
Sometimes things are going so well, you don't need a plan. Other times...
And the people in Detroit could move somewhere with productive economic activity. Why are they different from carriage drivers?
FWIW I used to be a protectionist. I became disillusioned with it when the choices around which things to protect, what to protect them from (foreign competition vs. automation), which status quo to lock in, and where we draw the boundaries of units that ought to be protected from each other, started to seem arbitrary.
I remember a particularly compelling line of argument from an economics textbook: okay, the US should make its own cars, but why stop at the national border? Why not have every state make its own cars? Think of all the jobs that would create! An auto industry in every state! But why stop at state? Why not make people sell their cars and trade to locally manufactured ones at every county line? Because it'd be a huge waste.
And, of course, many of the things we propose to protect "disrupted" something else not so long ago, sometimes in living memory. If we protect truckers from autonomous vehicles, for example, we will have to explain to the laid off railroad guys why we did not protect them from the truckers. Why we did not protect the longshoremen from the shipping container and crane.
It's the government's responsibility to take care of its citizens, absolutely.
Making people do work that they know is inferior to what could be done by machines (or foreigners) just seems like an extremely degrading way to go about that. I'd much rather see a good chunk of the output of "license to print money" operations taxed and redistributed.