I have reached the top 10 in paid health and fitness apps a couple times. Revenue is probably in the low hundreds of dollars for lifetime, and the first year it was out it made very little. Second year it started getting some traction. (apple also takes 100 bucks a year to post an app, so first year basically lost money)
It's hard since I don't really use paid advertising. I made it in SwiftUI and used a channel called SwiftfulThinking to learn how to code it, besides that just other yt tutorials as needed :)
Link to SwiftfulThinking channel: https://www.youtube.com/c/swiftfulthinking Link to app for reference: https://apps.apple.com/us/app/20-20-20-rule-resteyes/id64493...
I think it is possible for sure to build a business around a MacOS app. It just has to be unique enough for people to want to pay for it, and you have to know how to get it out there (marketing). Kinda like the iOS marketplace, just smaller, but thats not really an issue if you're solving a relevant problem for Mac users. Lmk if u have other questions!