Showing up late to world wars is a very American thing and this mindset would help ensure there’s a third world war to show up late to.
"America can't solve any of the world's problems" isn't the only possible logical conclusion from that fact, though.
Because free and open democracies are not the default way countries govern themselves.
And megalomaniacs like Putin who desire for a return to glory days do need someone of equal weight to push back.