Also I'm not sure that Xamarain or QT are really very relevant, HNSVBubble or otherwise.
https://insights.stackoverflow.com/trends?tags=xamarin%2Crea...
Dart also comes from Google and if it wasn't for Ad Words team it would be more dead than anything else.
Flutter is it very last opportunity to stay relevant.
Given that, I rather bet in dead technology with useful programming languages.
Flutter is the last option for Dart to stay relevant sure. You learn a programming language in a couple of days though so it just doesn't matter, and doesn't change the fact that in mobile world C# and C++ are just as irrelevant. I worked for years with C++, but I don't expect to ever again need it in a professional setting.
This is of course just from mobile perspective. Everywhere else Flutter is currently useless, and Qt/C# perhaps a good choice.
They aren't one pony trick shop.
Qt didn't not take off for free beer mobile devs, it is doing alright for the kind of corporations that actually buy development tools.
Again we aren't talking about SV HN kind of bubbles here.
And I am betting Flutter won't save Dart, specially with Android team doing JetPack Composer and teaming with JetBrains on Kotlin/Native portability between iOS and Android.
Long term, PWAs with WebGL and WebAssembly will take it all.
Qt is used in corporations that buy development tools yes. But not for mobile, it's mostly embedded/medical/automotive. Xamarin peaked after Windows Phone died as the refuge of C# development, but React Native ate its crossplatform pie. Are they used? Sure, as a very small niche. But the fact is that currently companies with money build two native apps, and those with less money to throw around use React Native to target both platforms.
It's hard to get excited about web technologies replacing native apps when they've been upcoming contenders since around 2007 starting with Symbian. Maybe it happens one day, maybe it doesn't.
Don't project your anecdotes in world wide projections.
Any numbers from Gartner reports or something, to prove how my little bubble is a niche?