- Multiple app versions are confusing when presented haphazardly to the user such as in search results.
- Removing old app versions reduces this confusion, but also eliminates their only vector for updates.
As for simply adding paid upgrades to existing Apps, picture the following scenario: Our [insert relative older than 60 here] purchased "Generic Picture App" 9 months ago. They have been recognizing and installing updates as presented by the App Store regularly and everything has been going along swimmingly. Then one day the developer finally releases the major version update: Picture App 2.0 - Now With Sparkles! What should our beloved relative see on the update screen? The update could–
- Display with a price, effectively making it an ad that wouldn't go away until purchased.
- Be ignored which would effectively treat this update as a new app.
- Create some new mechanism to indicate that this particular update is different from those previous updates, thus confusing the hell out our aging relative.
With each major version being a separate app, our dear relative could rely on the update screen to only provide free updates applicable to the software they purchased while providing developers with the means to update older versions with bug fixes, security patches, and of course a variety of methods of informing our sweet relative of their latest sparkly version.