[acdha]

One other factor is the degree to which hand-optimized code in general has been going away: Apple heavily encouraged people to use system frameworks like CoreImage, CoreVideo, etc. both to ease the transition and to take advantage of their significant optimizations, and that appears to have been followed by many developers. Adobe presumably still has a whopping case of Not-Invented-Here but I'd be surprised if a significant number of apps couldn't be ported with very modest changes.