Tataunka
I think it had to do with the beast races and the tail clipping issue which is still present in the mods. No one seems to know how to get around that. Cape mods for Skyrim all cut off the beast races' tails or have extremely terrible clipping issues.
AllSpark
I think it's part laziness, part time pressure on the programmers, but I'm glad there is a creation kit and modders with time and motivation, because without them these basic things wouldn't be possible But now we are way off topic