There are contractual obligations around changes to GSuite products (and their APIs).

For select users that are willing to advocate for themselves against Google and are covered under a binding, unexpired contract Google will likely let them continue using said APIs. Everyone else is likely to see APIs break at Google's whim, as most users aren't covered by custom GSuite contracts.

Contracts expire and can be not renewed.

Ideally your Gmail ought to be through a domain and services that add value via imap.

Then its impossible for the functionality to evaporate.

You are assuming they will retain imap functionality.

Ask the xmpp/jabber folks about hangouts.

Yeah I fully expect imap to disappear in the next few years. I've started migrating to domains I own for this reason.

I can see them keeping it around for enterprise for a bit longer, though.

I think it will stick around as long as it is the way the iOS Mail app connects

I don't know. Seems like an easy way to force everyone on to the iOS Gmail app. People aren't going to change their email address because it doesn't work with the iOS mail app.

I assumed nothing. If you sync regularly via imap you could switch providers tomorrow and lose nothing.

Good for you, that's the smart way to use e-mail. But most people, many of in tech and many of them knowing better, rely on GMail's web and mobile apps.

Also, unless you're using IMAP to sync the entire mailbox, you'd still lose. If your mail program only stores e.g. last 30 days of mail locally, and lets everything else live on the mailserver, then you'd only have 30 days worth of e-mails left.

This would be assuming that google opted to drop imap with zero warning AND you weren't smart enough to sync all your mail.

The first is out of character for google and the second is totally within your control.

All your mail is for most people merely GB at most per user.

Uh, you realize that imap support has been in GMail for its entire history?

Google Talk had XMPP support for its entire history... until they killed it

So?

Doesn’t mean they can’t get rid of it.

Getting rid of say outlook support would greatly weaken Gmail.

Furthermore if you have an up to date sync on the day imap support ends then you have all your email and need face only changing over to a new address or if you already use a custom domain logging on and changing the email provider.

They make it really difficult to use your Gmail account with K9 Mail. You have to jump through a bunch of hoops and "critical security warnings" for attempting to sign in with a non-Google app.