I bet a lot of California vineyardists would disagree about the Italians, and I could rattle off the list of early Germans ...and even some 2 buck wines can be great. The Mexicans, yeah, I would have to generally agree.
I bet they wouldn't. The early California vinters were mostly Italian. Ever hear of names like Mondavi, Martini, Sebastiani, Gallo, Nichelini, Simi, Parducci, Pedroncelli, Seghesio, Martinelli, Rafanelli, Riboli, Foppiano? There were a lot of Germans and other Europeans too, but the Italians dominated the California wine trade until relatively recently.
-ccm