About the Mac App Store
I had read mentions before that the Mac App Store is dead. About a month ago I hacked together my informer for Yandex AppMetrica and uploaded it to MAS. I started watching the charts (not for long, admittedly). In fact, there were 2 purchases at launch (I even know who both were from). The result surprised me.
Immediately first place in the Business category in the Russian Mac App Store. Of course, it is nice when your icon decorates the list of categories.
Still, just 2 purchases say that people really buy and download very few apps in the Mac App Store. Maybe free ones get downloaded more, but paid ones definitely do not. At least in Russia. It is nothing like the App Store for iOS apps. On top of that, the app reached 8th place in the store's overall top chart.
So it is not about the category. In other countries, apps are probably bought more often, but in Russia it is very little. Then again, piracy is much more widespread on macOS than on iOS, because there is no jailbreak hassle involved. That is probably why people here do not buy very often.