Fully agree (been an early Flutter adopter!). It's always the right too for the right job, declarativness makes a lot of sense for most UIs. UIs are surprisingly more complicated than one might think, there is accessibility/ theming/ keyboard traversal etc., just declaring UI and letting the framework figure out the rest has held up pretty well.

And because of the open source nature you can always drop down in layers, just a few weeks ago I made a very specific engine optimization, all while the application code on-top can stay declarative!

Perhaps. Certainly source visibility makes life easier as a dev who has to live with these frameworks on a daily basis. That said, I think frameworks should strive to have a wide and deep enough set of widgets that in most cases, devs won't need to resort to custom implementations to do what they need to.

It also doesn't fix problems inherent to declarative UI, like readability breaking down easily and certain things that would be a cinch in an imperative framework being extremely awkward to implement.