I think "staggeringly" is a good adverb in this context. The article focused on Android devices, so the author should be aware of the #1 reason of fragmentation

I think "staggeringly" is a good adverb in this context. The article focused on Android devices, so the author should be aware of the #1 reason of fragmentation in the Android landscape. AFAIK, only Google devices (Nexus*) reliably get the latest updates. Handset manufacturers profit when customers buy new phones to get new software features; free software updates dip into those profits.