[rubber_duck]

Umm - a large group of most popular productivity apps are cross platform and look nothing like native - from dev tools like IDEA, VSCode over Slack, MS Office, to multimedia tools like Adobe tools, almost all 3D modeling software like maya, max, audio software like Ableton, FL. None of the apps I use on a day to day basis look native (ie. like the apps provided by Apple)

You are confusing cross platform UI with frameworks that have programmer art widgets and no cross platform polish - eg. GTK+, FLTK, and even to some extent QT widgets (and many more). When people say widgets don't look native they usually mean "the widgets suck", you can create beautiful cross platform apps - Electron has quite a few because it allows standard designer tools from web dev.

Flutter is another promising development, but the desktop port seems underwhelming - it's obvious the widgets were intended for mobile apps, they will probably need a custom widget set to cover desktop UI - but the approach is sound.

[millstone]

The native apps you mention have heavy customization because they are meeting advanced professional needs. But these apps still participate in the platform's UI conventions. Menus, windows, etc. work like Mac or Windows users expect.

Electron apps are also heavily customized, but ignore platform UI conventions. The buttons may have lovely drop shadows, but basic interactions (menus, undo, drag and drop...) are routinely broken or work in some discordant, unfamiliar way. This isn't meeting professional needs; it's that web tech sucks for building actual apps.

And even if web tech improved, there's still the cultural bias towards re-invention and churn. Web dev will always cons up a button from a div and an onClick handler, no matter what the framework provides. There's no mechanism to get web apps onto a shared UI platform because the gravity of the web is dispersive.

[thwarted]

If MS Office was truly cross platform in look, feel, and operation, then finance people who insist on using Excel wouldn't also insist on using Windows just to use Excel.

All those specialized tools can get away with having completely-unlike-anything else UI/UX because people are paying for them and they are considered best(and only)-of-breed.

Electron apps are cross platform only in terms of them looking alike on different platforms, because they use the same widget set. If slack was a truly, full native app on OSX, it wouldn't look like it does.

[WorldMaker]

In my experience, finance people who insist on using Excel only on Windows generally do so not because of any reliance on "native controls", but on longstanding dependencies upon VBA macros with hard-coded dependencies on specific legacy COM components.

[rubber_duck]

I don't know enough about Excel but I highly doubt it's about the looks - I have Office installed on my MBP and the ribbon looks like I remember it from Windows.

I don't understand your point - non-native widgets are not a deal breaker and there are plenty of examples, Electron being the most common non-native cross platform framework recently (it has technical limitations but even the subpar performance doesn't make it a deal-breaker). So it's possible to create cross-platform UI frameworks and most of the the most successful apps I can think of are using some version.