For info and for the record, Google Nest Support's response I received today:
"I understand. Those are the recent updates that some features from Speaker Group are no longer available including such.
I will discuss this further with the management and see if this is something we can bring back.I know this is frustrating and I totally understand how you feel about it.
I suggest you help us submit a feedback using your speaker by saying "Okay Google, submit feedback" and say a short description of the issue so we can check it further with the right team."
So, the good thing (I guess) is that at least there is now a formal recognition that it's a design decision, and not a bug or user/device issue.
I'm not holding out much hope that the function will return (as it seems logical that a group cast would technically be connected to group volume management, and so falls in scope of the lawsuit). But I'll (again) submit the feedback as suggested, and hope more customers will follow suit.
In the meantime, an update on the move to Sonos....forget it if you're not Apple-minded. It is ridiculously complex to cast any local source from a mobile device to speaker groups from Sonos unless you use Airplay.
Which is Apple-specific.
FFS.
So. The search goes on.
This (intuitively) very simple function ('cast the sound -any sound- wirelessly from a pretty standard mobile device to a group of wireless speakers') apparently is ridiculously complex, or just not commercially interesting.
Pretty much the only option -which is still incredibly useless- I coukd find is 'party mode' setting on a group of mobile speakers like the Ultimate Ear BOOM series...BUT while that through Bluetooth offers the functionality I need, these speakers TURN OFF after 15 minutes of inactivity, with no way of preventing that.
So that is also utterly pointless in a multi-room home permanent setup.
URGH!
