Google management is neither unobservable nor unobserved.
Judging by the actions of Google's people in IETF, any feature that's used by paying mail customers seems to have management support. Management seems to like income, as far as I can tell.
I'm saying that while the technical lead may not be hostile towards IMAP, the "higher ranks" may decide it's not a business priority anymore and ask to get rid of it.