Keyboard shortcuts probably would work like I'd expect, people like me would go "Hell no, no keyboard shortcuts in browser application EVER", and power users would opt into that in an instant.
For how long?
You don't own the platform. Google PMs may decide to roll it out to everyone at some point to hit numbers.
What would you suggest people do. Self-host?
I'm just trying to understand why you posted this. It's generically true. Any company can change anything at any point. May as well just pack it up boys.
Yes, any SaaS can change any feature at any time. Some companies have different motives though. We're not paying for GMail. When customers pay a monthly subscription and can cancel at any time, you usually want to keep them happy.
The internal motives are also different. Are employees promoted for just launching stuff? Are they running out of helpful features to launch?
In principle, but look at all the ways Gmail bends over backwards to keep ancient UI preferences working. You can configure it for different inbox presentations, different densities, snippets or not, images displayed or not, UI icons or text, you can disable and enable threading, you can put chat and meet on one side or not, you can have keyboard shortcuts or not, you can remap all the keyboard shortcuts if you use them, etc etc etc.
You've got to use either Gmail, Microsoft, Protonmail, etc. I don't love them, but Proton is probably the best of a bad bunch.
this is not true unless you end up on an IP previously abused
if you don't want to take on the risk at all, there's email services for pennies / thousand emails
I'm seriously interested. Which ones would you recommend? Are they reliable?
I suppose, to your point, Google doesn't have to make it optional in other countries... But that discrepancy would seem to have a lot of downside (maintenance, optics, docs) for little upside (...force adoption against the will of users who would go out of their way to opt out of they could?).
Gear -> All Settings -> General tab (default) -> Smart features: Turn on smart features in Gmail, Chat, and Meet
Linked help page: https://support.google.com/mail/answer/15604322