Earlier quoted context omitted.
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.
Disclaimer: happy customer of FM for 8 years. 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 is…
I found a UI regression a few months back with the way threaded messages were working. Notified FM, they replied within a few hours acknowledging it was a bug and they would fix it asap. Fix was out within a few days, and they followed back to with me to confirm it was fixed for me.