International trade is complicated. I say US here but almost everyone put tarrifs on Chinese EVs. Germany's economy for example heavily relies on the auto industry, and a collapse could mean a lot of problems.

You also don't want a monopoly. If China are the only one's selling cars, it won't be long before they are no longer cheap. We speak of cars but it's the same for food. You don't want a foreign country to have an economic handle on your food.

It's also worth noting that these other products are often cheaper because the people making them have a lower quality of life. We don't want to end up in a race to the bottom.