This line of thinking is quite disingenuous, because the vassalization of Europe has always been desired and worked towards by the US. If Europe would "stand on it's own legs" that would mean the US would lose the last bit of influence across the pond, would mostly be on the losing side of military contracts in the old continent and would, after losing their grip on the near east and east asia, be mostly relegated to the Americas. While that would arguably be a net benefit to the entire world, it's more than doubtful that US politicians would desire that outcome.
So no, the US doesn't want Europe to be independent, the US just wants these juicy €€€ in their pockets and sell their overpriced and in many regards underwhelming weapons systems to guilable Europeans after some serious lobby work. That's a more accurate description of what the US seeks to achieve with empty threats of leaving NATO (their biggest platform to gain leverage over the majority of western nations). They benefit by far the most from the alliance and thus it's only logical that they spend the most money. Because ultimately NATO is not a defensive alliance or anything idealistic like that (probably a hard pill to swallow for people around the age of 40-50 who grew up with that Image), it's a platform to influence and shape relations between the US and western aligned nations within the organization. That can take the shape of providing basing, which the US always happily utilizes, but it can also take the form of the sales of military equipment, exercises or the US influencing foreign policy to their benefit through the NATO framework.
