However, now what do you sign into your Android device with? Google's products work... poorly... across multiple accounts. I needed to change my email address a number of years ago, which is impossible with Google's apparent use of email addresses as a primary key or something, and my Google account has had to live in a very messy state ever since... the old address has to be the core of the account for all services, even if I'm handing out and sending as a new address... and that account is an extra security vector into it... (Meanwhile, Microsoft just lets you add and remove email addresses from your Microsoft account, including changing and removing the primary.)
I wonder if Google will support a workflow for users "leaving", whereby the can keep their "Google Account" under the same email address, but with Gmail disabled.
This could be a reasonably low friction way to keep the system working without breaking the "email address is unchangeable per-account" assumption - the underlying Google account can continue to exist, even if the associated MX record disappears, or Google Workspace ceases to provide service.
This is how Google accounts work today if you ignore the "default" sign-up path, and take the route where you create a Google account under an existing external email address.
