Why do S&H start Civic generations so early?

[Remy Renault]

If Western Continental Europe is on the same timeline as the US then they appear to be having a very subdued 4T this time around, just like circa 1870. But I'd also be willing to argue that not every society is on the same 80 year cycle. I think Western Continental Europe has 150 year cycles instead. 1789-1945 was a cycle unto itself, just like 1648-1789 was before that. Sure, in the 1870s you had the Franco-Prussian War as well as German and Italian unification, but Europeans don't view that era as a time of great upheaval with "no turning back". Europe had a protracted 4T in its 150 year cycle that lasted from 1914 to 1945. How was WWI not a 4T event for the French, Germans, and Austrians? I agree it wasn't a 4T event for the Americans. WWI changed the map of Europe more than WWII did while the latter changed the balance of power.

And it shouldn't need to be said there are other cyclical theories of history out there. S&H's isn't the only one.