While the EU welfare is not that much larger than the US (maybe 5% more of GDP), the US also has much more money, a larger portion of the population working, and higher population growth. They also have the technical and business knowledge in tech that the EU lacks (e.g. silicon, rocketry, hyperscalers, etc).
It also has an ever-increasing amount of debt and an aging population, e.g. the US is expected to spend more than $1 trillion a year on the interest on the debt itself, or $7,800 per household per year.
