Wouldn't using ones own domain and gsuite alleviate some of these issues? If Google were to shut down your account, you could update your mx records to a different mail server such as fastmail or self hosted as mentioned elsewhere in this thread, and be back up and running relatively soon (of course you still wouldn't have your connected YouTube/G+ etc accounts).
Although as I write this it occurred to me, you would likely loose all your contacts and calendar unless they were backed up prior...
Although as I write this it occurred to me, you would likely loose all your contacts and calendar unless they were backed up prior...