I can't entirely speak for Android, but I assume that Google has similar nonsense (as evidenced by sideloading being a pain to the average user)
For Windows, Linux, and MacOS, there's no real need for them, or not enough need for them to exist. There are no policies or guidelines to follow, there is no 30% tax.
The browsers people use on desktop devices provide everything that developers need and can reasonably expect of the platform. There aren't any usability differences, there are barely any performance differences, and there are barely any feature differences.
In fact, I think many desktop end-users would prefer the app to be web-based because it feels so native.
In addition, it's what another commenter said - if it can't be on iOS, then what's even the point of having one?
For Windows, Linux, and MacOS, there's no real need for them, or not enough need for them to exist. There are no policies or guidelines to follow, there is no 30% tax.
The browsers people use on desktop devices provide everything that developers need and can reasonably expect of the platform. There aren't any usability differences, there are barely any performance differences, and there are barely any feature differences.
In fact, I think many desktop end-users would prefer the app to be web-based because it feels so native.
In addition, it's what another commenter said - if it can't be on iOS, then what's even the point of having one?