I remembered the Spanish phrase when I read this news item. Back in the ’60s, Vespas were the height of cool as far as Mods in England were concerned (read about them here). In Spain, which was still a relatively poor country, they were very much luxury items. Hence, people said that Vespa was an acronym for “vosotros españoles seréis pronto americanos” (with America viewed as the leading consumer nation, though I can’t quite see them driving Vespas).
For anyone interested in the Mod culture, the movie Quadrophenia is a must.