To some extent Notley Maddox seems to me right.  European Westerns did
follow the American genre because it was profitable.  But they have
their own differences. Frayling on Spaghetti Westerns shows ways in which
(while paying lip service to the American tradition) they engage with
European values.
Leone's westerns, for instance, can be seen as deriving their darkness
ultimately from fine traditions of Machiavellism, from the kind of
monsters that stalked Webster's Jacobean drama, from the iconography of
the Catholic church, from the experience of a people (hence the move of
the dramatic location from the US to Mexico) used through long
generations to living under despots, from the gods and demons of the
classic pantheons.  And they don't resonate to the thrills of the
American Dream, as you'll have noticed!
Frayling's theoretical bibliography (he refers to Method) lists those
books he used to give him an analytical apparatus - a long list, which
includes Althusser, Barthes, Wollen and others, including Will Wright.
The last time I tried to order it for students, Frayling was out of print
in the UK;  but it is a fine study, well worth while pulling from the
library if you are teaching this field.
Good luck
John Izod