I'm not sure that's the case really - the Mustang is considered a "sportive" in Europe, so in the same class (nominally!) as Porsche 911, Ferrari, Mercedes Sports etc etc.... It has been the best selling "Sportive" for a few years, so there is clearly a market and a desire for some Us cars. But there is definite;y a "European design" and a "US design". back in the early 2020s we went to the Concorso at Villa d'Este, on Lake Coma, and had an interesting chat with Ed Welburn, then GM head of design. He was there with a Cadillac concept that outwardly was pretty fab, and he was justifiably proud of it. But when we looked at the inside it was sooo 80's! It didn't suit the outside of the car and was so far removed from the other offerings on show from the usual European suspects, VAG, BMW, Mercedes etc....
And I think that's some of the problem, that the US cars are not what European buyers want necessarily.
Where GM fails is that it has some very strange ideas about what European customers should have, colours and spec wise. They have failed to grasp that US cars are seen as having "everything", so that is what we expect, not a half hearted list of options or restricted colour pallets.