Trench warfare was the future -- but apparently during the intervening 60 years, those Euros who saw it first hand were all gone by the time WWI rolled around.
But the Brits had a taste of it in the second Boer War and the Russians saw it at Plevna.
There was a lot of chauvinism to the European observers. “Yes, that may be how these American amateurs fight, but it has little to do with us professionals.”