The more relevant question to ask is why American car manufacturers, with the exception of Tesla, struggle to export in volume and seem to have largely withdrawn from the international market.
I think it is simply because they are no longer competitive enough to survive without a lot of protectionist measures keeping superior products off the market. That works in the US of course. But it has also killed the export market.
The European perspective to this is that (Tesla excepted) you don't buy an American car because of performance, cost, efficiency, build quality, etc. A European might buy one because they are big, loud, and a bit obnoxious though. Seems to be a thing with some of the rich people here in Berlin certainly.
But you just don't see a lot of American cars here. When you do it's either some old sensible Ford model from when those were still being made; or an imported muscle car with some large engine making a lot of noise and smoke. I even saw an actual truck in Berlin a few months ago. These are very rare in Europe. They just aren't very practical. You can't navigate small streets with them. And nobody in their right mind would use these commercially because the fuel cost would be a big overhead. They are expensive toys but otherwise not competitive. Not even close.