I would argue that most users expect that their software continues to work on new operating system versions without being forced to upgrade (which is easy for f

I would argue that most users expect that their software continues to work on new operating system versions without being forced to upgrade (which is easy for free software, but less so if the upgrade costs money and the users are entirely happy with the feature set of their current version). PS: also, looking at Windows specifically, new operating system API layers don't necessarily mean that they are an improvement over the older APIs.