Not to mention, so far most of the NATO missions are about participating and helping in US wars on MiddleEast. And it is not only about military budget. But also the budget to deal with immigration issues after MiddleEast conflicts.
I don’t think it is fair to blame NATO. They did their best so far and they deserve the support.
Doing their part does include purchasing modern aircraft that are capable of participating in missions in support of an overall strategy of air superiority.