I don't think this is very debatable. Consider the fact you might be in the vast minority of users.
I'm a dev/technical user, in the key audience for native look & feel powertools, yet the main apps I use on Mac are still Chrome, Spotify, Slack, VS Code. None of these use the desktop's native theme.
Imagine the case for non-technical users.
Average users expect apps to have a custom look and feel. Ever tried SnapChat?
Most non-technical users I know - elderly couples, family, etc don't even install apps, they just use what their OS gives them. I don't know any who does not have VLC or LibreOffice however (but that may be a french thing)
I did say "non-technical", which is open to interpretation, but I did not mean 'computer illiterate' (i.e. only uses apps given by OS).
The discussion here is really about average users, and the baseline assumption here is that we are talking about apps that don't come with the OS, that we'd install, since we're devs, creating new stuff.
> I don't know any who does not have VLC or LibreOffice however [...] (but that may be a french thing)
> I did say "non-technical", which is open to interpretation, but I did not mean 'computer illiterate' (i.e. only uses apps given by OS).
I was about to say "you know that the median mobile-device user has one third-party app installed, right?" but then I thought better and Googled it first. This used to be true, but the stat is far out-of-date; nowadays the median mobile-device user has 40-to-80 apps!
I'm kind of shocked how much user behavior has changed, honestly.
macOS is exactly where people expect native theme. People aren't using the apps you mention because they like the look of them. They're using them because they believe the functionality is better than the native-looking alternatives, or because they have no choice (e.g. with Slack).
"people" is "most users of the platform". A consistent native platform experience has been one of the cornerstones of macOS since even before OS X came along.
If you ask most people, they probably won't know to identify this as a desirable trait, but what they do know is that if they launch a non-native app it will likely not look or behave according to their expectations. For example, I'm an expert user and even I'm still tripped up by the fact that Slack has a rather anemic menubar, and Discourse's is even worse.
In the native vs not-native look and feel discussion, I hold the opinion that different platforms have different answers. In MacOS, users expect a native look and feel, or at least something close to it.
Windows, Linux and Android users have no such expectations. In fact, in the case of Android, a non-native look and feel could be considered a positive thing since the native android look and feel is kind of terrible.
I heard about that a long time ago, back when it looked kind of dead. Glad to see it's still under development. I'm skeptical though, does it actually support all of Slack's features (or even a majority of them)? The screenshot is rather minimal, showing nothing in the way of unfurls, no formatting beyond a link and an @mention, no userlist, no channel info, no pinned messages, no reactions, etc.
I'm a dev/technical user, in the key audience for native look & feel powertools, yet the main apps I use on Mac are still Chrome, Spotify, Slack, VS Code. None of these use the desktop's native theme.
Imagine the case for non-technical users.
Average users expect apps to have a custom look and feel. Ever tried SnapChat?