I'm pretty sure that most people are only dimly aware of the existence of the quoted part at the bottom of an email. Mail clients routinely hide it by default, and in most cases it's never needed for anything in today's email conventions. Most clients now group conversations to threads, and most emails aren't long or complex enough to require much context anyway, never mind the custom of interleaving quotes and replies.

The vast majority people didn't yet use email back when bottom posting was good etiquette and top posting was discouraged. They're simply not aware of the concepts, or the controversy, at all. Even old-fashioned snail mail letters, for those who still remember such things, didn't usually include quoted passages, even though getting a reply to one's letter could easily take weeks if not months.