There are plenty email providers out there. Free and paid. It should not be a problem for anyone to switch. Moving off of Gmail doesn't mean to self host. It is a bit of work to tell anyone about your new address, but that's it.
For a non-technical user (like my mom), this is a herculean task.
Over time, the old gmail account will lose its importance, and there'll be no real risk if Google decides to ban it.
The effort is only one time or one day at max. And the rewards are worth the time.
I just keep the old GMail for now, and whenever I receive a valid email there, I visit the sender website to update it.
This depends on you remembering your "low-volume important accounts" like government websites you visit once a year, but otherwise, I would not cry if my imgur account got lost or something eventually.
Edit: Looks like LastPass does it with a screen scraper https://support.logmeininc.com/lastpass/help/how-do-i-update...