Yes, I think we can all agree that the US has become a less predictable partner when it comes to NATO and defense. It seems obvious to me that European countries need to pool their resources and work together to build their own capabilities.
I didn't realize how fractured European politics are though. To my US-centered brain, it's a bit like California and Texas trying to work together to do... pretty much anything. It just wouldn't work, and yet that's roughly the challenge facing Germany, France, the UK, Italy, Poland, and the rest.
The numbers tell the story: among just the top 10 European economies, there are 5 different main battle tanks in service. Seems like there would be some easy wins from an economy of scale perspective. Ditty pretty much all the big expensive things that militaries want. Jets, missiles, artillery systems, air defense systems.