Ok. Tell that to our multi-nationals. I'm sure they'd be thrilled
to see an isolationist US.
Sure, why not? The US was mostly isolationist for much of its history. Foreign war doesn't really help our popularity and bad popularity really doesn't seem to help our currency. Not only that but most of our military interventions really don't help our businesses very much. The jingoists are the ones who love our wars, the business class wants stable markets and lower taxes, both of which could be provided better with less war.
Oh, I'm not saying Britain was particularly to blame. Though had they stayed out of
the wars, they would have prolonged their Empire a bit longer. The Bismark alliances
would have left France without any allies. Alternatively, there was even a possibility of
an anti-English alliance. But, SOME war probably would have occurred to finish off such
a power.
However, they had allied to enter that war and Germany had acted in manners that offended their sensibilities. Really though, you assume that a war must be necessary to hail the end of a power. I assert that no war is necessary and no war is likely.
As to the second war, it strikes me that it was simply the necessary conclusion. Germany
was too humbled by the first, yet left in a tremendously powerful position. But, all of the
countries were too weakened to really be able to go on fighting. Similar 'truces' have
happened again and again through history.
Germany was too hurt by the first. Heavy conditions placed upon it the Treaty of Versailles, combined with an economic depression would cause war in just about any nation. Now, it is true that they were bitter about the first war however, that alone did not lead them to a leader willing to go to war.