Spanish, Germans, and French play in foreign countries more often, as well, though.
Not a critique, but there's definitely a cultural influence there I think. I think the higher wages are a big part of it in England, but once you get away from the top of the table it falls off pretty dramatically. Leipzig, Wolves, Villarreal, and Fiorentina all have comparable wage bills. French clubs are paupers, which explains their movement certainly.
The language factor has to be considered. A lot of players from the rest of Europe are at least bilingual, but the vast, vast majority of English players are monolingual. Obviously there are plenty of players who move somewhere where they don't speak the language, but it definitely helps if you're Belgian or Dutch for instance and speak fluent English anyway.