These seem like valid concerns at first glance, but I feel these are not really issues in practice (only in theory).

>> - They inevitably don’t look or work like native apps in ways both big and small, frustrating and annoying users. (... the spell-checker doesn’t work right or text selection is janky or unavailable where it should be, certain short-cuts work differently or have different gestures or keys, etc.)

as `coldtea` points out below, this is not really an issue in today's ecosystem. Branding themes are more prevelant on most apps people are using than not.

>> they don’t get updates to native controls... e.g. if the OS adds some new drag-and-drop capability to text fields the framework doesn’t get it unless and until the framework is updated (and the app is updated to use the newer version of the framework). Of course, some things are never deemed important enough to be adopted by the framework.

If people are writing cross-platform apps and want to use new platform-specific features, wouldn't they have to write platform-specific code anyway if they were native? I'm not sure this is a newly introduced problem in any sense.

>> - Ambitious frameworks that really try to minimize the gaps between apps build with the framework vs native app grow to be very large. They take on the role of the entire app-facing OS API, which is truely massive in today’s systems. This leads to slow-loading/building, resource-hungry apps. Each app becomes a mini-OS unto itself.

I guess that's valid; but I'm curious about cases where code-heavy app sizes have actually hindered app downloads. I don't really know, but I haven't heard that this has been a big problem? For reference, a hello world flutter apk clocks in at 5 MB.

>> - there are cross-platform issues, like fonts that fit on one host OS get cut off in another, or differences in volume control etc.

Flutter renders all of its fonts itself natively, using the same way Chrome does it. Has this been a problem?

>> - dealing with the cross-platform issues the framework doesn’t solve becomes very difficult for the app developer. They’ve got to find a way in, through, or around the framework (in an area it already isn’t handling well).

>> - many potential third-party tools will have native support and bindings but most won’t make accommodations for your framework, so you end up having to support that yourself, or do without.

Is this a remark on an incomplete cross platform framework (i.e., flutter needs more features) and that it hasn't reached enough popular usage, or that cross platform frameworks have this problem? If not, it feels like the alternative to not using a cross platform framework is to write everything for each platform in a platform-specific way, which might be considered much worse. What's the issue at hand here?

>> - devs have yet another set of tech and tools they have to master. And I mean devs in the wide sense here, designers, coders, testers, etc. Some also have to become masters of how the framework and each host OS interact, in order to debug the inevitable problems.

This feels like an emotional assessment of having to learn something new. If this technology is meant to simplify/remove problems that people have today, then isn't it worth learning?
I guess you might feel this way if you felt that flutter isn't adding anything of value to other popular solutions today.