Hangouts did very much the same with XMPP, a move which a Googler once suggested to me was viewed internally as a betrayal of the company's values.
I think we may be approaching EEE territory with email: Gmail's already centralized a large portion of the email industry, to the point that Google has about two-thirds of all emails on one side or the other, and now they're moving into introducing a proprietary email format (AMP 4 Email), which isn't being developed in a standards-focused way.
I'm sure the same argument could be made for their push into RCS over texting, browsers (now pushing Chrome-only websites and features in a lot of places), Android (embracing third party OEMs before moving into locking down much of newer Android functionality and launching a first party iPhone competitor), etc.
If there was a movie quote that best exemplified Google's business strategy, it would be "I have altered the deal. Pray I do not alter it any further."
AMP for email does seem a good example.
RCS is not developed by or supported exclusively by Google. They weren't even the first; Vodafone had it on their phones for years. Google is late to the party.
My opinion is not that Google is ethically above doing EEE; it's that they're often too disorganized and erratic to actually pull it off even if they wanted to.
Just having the best app isn't EEE.