> Firstly, Gmail's success is entirely predicated on the health of the global email ecosystem. Gmail does not, inherently, have any network effects (unlike FB, messengers, any other comms tool of Gmail's scale)

Google initially federated with XMPP, until you had critical mass and shut out the rest of the Jabber/XMPP ecosystem.

Of course now you seem intent on killing your _own_ messaging product so it's hard to divine any self-consistent intent here.