You can backup your data but the big fear that caused me to move off was GMail. When Google drops the ban hammer on any of its services (eg. YouTube for using too many emojis) it does it at the Google account level which kills everything. Even worse I've also seen reports Google continues to accept new email and the sender has no knowledge that you're locked out and unable to respond.

I'd wager that the vast majority of people don't, or certainly don't for emails.