One of the problems with complaining about NATO as an effective partner for mobilizing Europeans for the defense of Europe is that NATO is also important for keeping America in Europe for our own objectives.
Never forget that Europe is an asset, too.
We may be unhappy that Europeans won't mobilize their economic and technological power for effective military power as allies; but we'd be more unhappy if someone else hostile to us managed to harness that economic power, large population, and technology to create significant military power that could be used against us.
Nor should we forget that Europe is a power projection platform for our forces into an arc of crisis from West Africa to Central Asia.
So let's not talk so easily about why NATO is worthless.
Whether the threat is a proto-Soviet Union in the European Union, a revived and aggressive Russia, or demographic changes within Europe that threaten to nullify a still generally Western outlook, we need to defend Europe for our own reasons even if Europeans don't much feel like it.