Maybe because this iOS issue remains unresolved?
https://www.facebook.com/skylines.pr...52378401447918


There will also not be a version of XCSoar for iOS due to Apple's restrictive distribution policy which violates the GPL license.

Q:
"Now the question that thousand of pilots who have an IPhone/Ipad must be asking including myself, is the next release of the XCsoar 6.3 version available for Mac IOS Iphone and Ipad etc? I hope so"

A:
"No, it won't. This question has been asked many times already, but due to licensing problems we are simply not allowed by Apple to release a version that would run on iPhone/iPad. The Apple AppStore demands that all applications are ONLY distributed over the AppStore and that conflicts with our open source license which demands that no-one should limit anyone in distributing our piece of software in any way you like. We certainly would like to see it running on iOS devices too, but unless Apples lifts this restriction there is not much that we can do about it... Sorry!"
Source: http://forum.xcsoar.org/viewtopic.php?t=230