The US isn't the navel of the world. It is one country that is slowly removing itself from international trade and the international scientific community.

The European Union has many friendly trading partners left in the world and is also receiving an influx of previously US based talent. The trade decisions of the US aren't forcing the EU into isolationism. This is where your argument goes wrong IMO.

The US government has announced that it plans to actively support extreme right wing parties in the EU. If this comes to pass, it is a direct attack on political freedom in those countries, separate from any economic policy decisions. I don't know how well EU countries can defend themselves against this in the short amd medium term. Some counties have better defenses than others. But I see virtually all of them struggling.