This article finally prompted me to do what I should've done a long time ago, which is to create a Fastmail account and begin importing my Gmail into it. I've seen this story far too many times, and no longer will I say "yeah but it'll never happen to me". Setting up the import was insanely easy, and my Fastmail account is now configured to enable me to send using my Gmail address from directly within Fastmail. Plus…
But even then you have to trust FastMail not to lock you out. Sure it's a paid service so less likely and I'm sure their customer service is better. But it doesn't fix the root issue of being dependent on one party.
The single time I needed support from them, I was replied by a person that understood my problem and while they didn't fix it (it was a feature request) it was added to their backlog.
The suggestion appeared live like a year after and was contacted saying it was available in case I still wanted to use it.
From Google, on the other hand, I never got a human reply to any issue. The one that pissed me off the most was that my location history pre-2015 disappeared for some reason and I was using it to geotag old photos. No response, no acknowledging of the issue, nothing.