That said, I literally only use Flutter as a hobbyist.
I made a basic web game for a friend, and a small web app that helps me manage my music lyric videos. I ultimately picked Flutter because I find it easier than actually building websites.
Dart is amazing.
But I'm not deploying to millions of users. At most 10 people have seen my Flutter apps.
It's VERY good for creating quick crud apps with Firebase.
Just counting the number of us who have it installed and might of spun up hello world says nothing about it's actual market share.
To be clear, I absolutely love Flutter, but it's still not something I really see job listings for.
Dart is great too BTW.