It will likely not continue

Do you mean Google's support will likely not continue or that the project will not continue if Google pulls its support.

The way I read it, it looks like OP is saying that in case Google pulls out, then it will likely not continue.

And I tend to agree with this. I can foresee an initial counter-push for the first year or so after google pulls out, but then the project will die its own death.

However, with Flutter specifically, I have a strong feeling that Google won't pull out. Esp given how Dart was kind of a big flop for years after the initial release, and Google still kept it around until Flutter came into existence, and then made a hard push to continue with Dart. At the moment, Dart is the best and most popular it has ever been.

Not Google per se, Ad Words team rescued the project from closing down as they had a major effort to port from GWT to Dart 1.0.

Ad Words is what keeps Flutter alive.