i know you are good at math, fragmentation is a factor of products (X) Operating Systems (X) Screen resolution. When looking at andriod vs IOS, its a huge difference. Even with my nexus devices (4 and a 7 tablet) there are some apps the new kit kat just wont be able to download since the app is "not built for this version of operating system". And that started even with 4.3. On my iphone and ipad, i have not seen a single issue of this.
I don't have KitKat yet but I've been using Android since Gingerbread and I have never seen this before.