Not everyone offers staunch support to a single platform. Some people update their Android devices to Apple, or vice-versa. Maybe a person gets an offer and switches to another platform that is not in the "top two", even if briefly. Furthermore, there are some people who use more than one platform at the same time, concurrently. Many companies sell the same application on different platforms too. Should users demand their app purchases are honored across multiple platforms? Do you agree with buying the same application multiple times at is happens right now (once per platform), or would your rather demand a single app-buying which gives you more than a platform? After all, you are supporting their app and you're a single buyer. Perhaps they should account for this fact giving single-person rights to all platforms, as opposed to punishing users who engage in more than one platform routinely.
Uhm, this is like saying that if you purchase a Fight Night boxing game for the Xbox 360, you expect it to work also on the PS3, the Wii and the PC. If they could incorporate that, then companies could also incorporate a single purchase which would be honored across several mobile platforms. The problem is, this would be a but hard to incorporate and would definitely decrease the revenue of the developers. Hard to do + less revenue = no no for developers.
