The problem with Trump's mindset is that he stupidly believed that the EU was weak because they had to be. They did that by choice. The EU chose to stay weaker because our country was an ally and has always promised to have their back.
Threatening to cease doing that with words and actions didn't panic them, because they've had a plan in place for when/if that happened for years, probably for decades. It would be short-sightedly foolish to blindly believe the US would have their backs forever with no contingency, but that's what Trump's two-dimensional thinking tells him.
So now they will become the new superpower, and we very well are about to learn what it's like to have to depend on others for strength and security. And honestly, we had it coming, acting like dumbasses and letting self-centered idiots be in charge.