I have no idea if the service has a future, but your fear of what may be inevitable is reason enough to start the torturous journey now IMHO. Better to start now and have enough time to plan it out, than rushed into something and put your archive at risk.
The shifting of your email archive is simple enough if you have a laptop with Microsoft Office installed (or a suitable Outlook alternative) and can dedicate enough time to setting up both your BT and “new” chosen email service, and then studiously Copying the folders between the accounts. I’ve done this many times for people over the years. TIP: check the size of your folders and run some tests before you do it for real. Depending on the strength of your connection these copy tasks can take a while and/or time-out if you try to do too much at once.
As far as Online Accounts are concerned, remember just because your login ID is an email address, it doesn’t mean the actual email address registered to that account has to be the same. You should be able to retain the login IDs as they are now. Just go in and change the actual registered email. A lot of accounts won’t even let you change the login.
ISP email services have long been on the slide. Unfortunately many people have learned the hard way when switching suppliers, suddenly realising they will lose a service which these days is pretty critical to everyday life.
Hope that helps and is food for thought.
