What then, if Flutter is not to be relied upon beyond 2 years, should you be considering? This is the question left unanswered at the end.

It was precisely this question that brought me to dart/flutter, as well as being truly cross platform, over the multitude of JavaScript Frameworks.

I hope Google doesn't end the dart/flutter development.

It's quite unclear what the frustration is about. I'd like to see the author elaborating them by giving concrete examples

I think this author is missing some key pieces. Kotlin was not developed by Google. It was made by JetBrains. Google decided to use it for Android development. JetBrains has been working on cross platform tooling for Kotlin from the start. This is nothing new. Although the article doesn't say this - it alludes to it - Google is not making competitive cross-platform products in-house.

Bad programmers love to blame everything on their tools...