GDP measures the strength of the economy. The only thing the EU has to do to keep its quality of life, is to have a stable GDP per capita. Obviously having a stronger economy is helpfull, but it comes at a price. For example Germany is pretty close to as efficent as the US in terms of GDP per hour worked. It is just that Germans do not work as much as Americans, due to choosing to have more vaccation time and shorter workweeks on average. Hardly an awfull choice. To use another example. In the US you have to have a car, as everything is extremly car centric, but in the Netherlands you can just ride your bike to work. A car costs more then a bicycle and it requires fuel. Even better cars make people sick, due to bad air quality and well accidents. So bicycles, whcih provide light exercise actually are bad for the economy, as fewer workers are needed to put them together, provide fuel and provide medical services. There is a lot of stuff like that.

This is not to say that Europe can learn nothing from the US. The US ability to create innovation is great and only matched by a few European countries. That being said, looking only at GDP is like judging somebody only by their income. It just does not tell you, how good their life really is.