As my kids get old enough to get an email account, they won't be gmail.com accounts. But I will probably never cancel my gmail account which presumably at some point will have the same stigma as a hotmail or yahoo address does now.

That's the real threat to companies who get to Google's size: their customers dying more so than going to the trouble of switching.

edit to add: Which, I'd guess, is why Google has invested so much in Classrooms.