That's an extreme oversimplification.

Most apps are budget constrained - doing 2x native over flutter budget doesn't get you 15% better UX. It probably doesn't even give you two working apps in the budget. And getting to them you're still likely 2x bugs and worse UX because of the time spent redeveloping common shit.

If you're not budget constrained, have a team that can execute better UX without flutter, and this matters to your app - go for native. But there's so many scenarios where it doesn't.