The NATO countries are quite happy to be dependent on the U.S. because military capability is hella expensive. NATO can't even get their own military spending target to be taken seriously, and that's an order of magnitude lower than what the U.S. spends. If by "hegemony" you mean "the U.S. pays for everyone else's defense, and gets some amount of reciprocation (most likely worth a lot less than 20% of GDP, so hardly a fair trade!) in the form of favorable foreign policy from the countries it's paying for" then the U.S. is obviously a hegemon and no one among its "clients" is seeking to change that in the slightest.