> It's also worth noting that many countries were probably taking advantage of the US's old management (e.g. most of the rest of NATO severely under-investing in their defense, expecting the US to spend to pick up the slack)

yeah, that is how being a hegemon works. There are benefits and drawbacks to that, but lets not pretend like USA didn't get a lot of benefits out of the arrangement.

In any case, seems like that era is mostly coming to an end.