I've been playing around with Google's new cross platform effort lately, and it looks to be coming along quite nicely. I have also been thinking a lot about what Flutter's future might be.
In it's first phase, it's "just" a cross platform way to write highly performant visual applications, but I think it's just Google's first step in their plan to make their new operating system, Fuchsia, relevant.
At this point it's no secret that Google's working on a new operating system. There are not too many details yet, but one thing that's been uncovered is that Flutter is going to be the SDK or app development kit for this new operating system. In a best case scenario, developers are going to see their apps run with little or no change on Google's new OS.
I think one of the main difficulties when trying to launch a new operating system is getting users to the platform. Without apps, users are not going to make the jump, but without the users, the developers are not going to make the jump either.
What Google is trying to create however is a situation where a lot of app are going to be able to run on their new operating system right away. "Want to support our new fancy platform? Make these 5 small changes and you're good to go!". Or even better: "Run this tool and it will tell you what will have to be fixed and whether it can be fixed automatically by the tool."
Samsung is trying to make a push with their new operating system, Tizen, too. While I'm still very skeptical whether they'll succeed in their quest to supplant Android, they're also making a similar bet, but with .NET Core. .NET Core is going to be the main SDK for Tizen, which makes Samsung able to tap into a pretty large developer base that way.
How all this works out will only be known in the future, but I think Google might just have the power and influence to force (another) new operating system into the market.