TL;DR The app stores are messy to deal with and come with many restrictions that shouldn't be there, considering they're completely Apple's solutions, and Apple

TL;DR The app stores are messy to deal with and come with many restrictions that shouldn't be there, considering they're completely Apple's solutions, and Apple could do a whole lot more within its control (but has not been doing so far after all these years). Conversely, the only reason the App Store on iOS and tvOS are used is because there's no other way to distribute the apps to a large base of customers (at least for non-jailbroken devices). Why many apps don't use the Mac App Store: 1. It's primarily because software distribution on the Mac had different mechanisms maintained by developers for decades (or from before the iOS App Store and the Mac App Store came to be). Many old time customers are used to buying direct from developers and having a way to have a direct contact with the developer. For example, AgileBits (maker of 1Password) had to go back to retaining its own sale/distribution mechanisms after declaring that it's going MAS only because of long standing customer backlash (and probably acknowledging that it was anyway forced to maintain this for its Windows app at that time). 2. The App Store on iOS is deficient in many ways, when you consider that it doesn't allow (easily implemented) trials, upgrades, etc., that many users from the PC/Mac computers side are used to. The Mac App Store is even worse than that. Read this mess about free trials on the App Store (iOS) from a few months ago (June 2018), written by developer Daniel Jalkut of MarsEdit fame. [1] 3. The sandboxing restrictions that just don't work for several apps, means it's too much of a hassle to change (or cripple) one's app just so it can be distributed by/through Apple. 4. The 30% cut that Apple takes is probably a lot higher for developers who already have had a system in place for a long time. But some newer developers have moved to the Mac App Store as the only means of distribution (Pixelmator is a popular and notable example that went MAS only and has stayed that way). 5. For developers who care more about customer relations, Apple's country restricted stores and the lack of portability mean that a user who moves from one country to another would usually have to go through some confusing ways of updating apps bought from a previous country. As for subscriptions and in-app purchases, those cannot even be transferred, AFAIK. Even now, subscriptions cannot even be canceled before they expire (you'd have to contact Apple for that and try to work it out). The app stores are completely Apple owned and controlled, but yet they don't have any easy solution for people who travel or move to another country (or to other countries) either temporarily or permanently. [1]: https://bitsplitting.org/2018/06/06/ersatz-free-trials/ https://bitsplitting.org/2018/06/06/ersatz-free-trials/