People won't switch because sites are hectoring them with lectures about how something they might be fine with is actually awful. All it would take for them to

People won't switch because sites are hectoring them with lectures about how something they might be fine with is actually awful. All it would take for them to switch are compelling apps (whatever definition of "compelling" applies to each person) which exploit the capabilities of, and therefore require, the newer browsers, and whose existence is advertised to them. Not "your browser is bad and you should feel bad", but "this site is awesome and will make you feel awesome, there's just one thing - you need to install this awesome browser to get your ticket to awesomeville". Same as any other platform.