[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.