So many factors many of which have been mentioned.
First was the GameCube release it brought in a ton of sales even though it was on a dying platform. It was the launch title for Wii the flagship title introducing motion controls. There were what 7 or so games to choose from launch day LoZ:TP was the no brainer launch title.
Add to this Nintendo's decision to go with a darker gritty art direction. A mature Zelda the title fans had been waiting for since the 2001 SpaceWorld video. Gamers that were dissapointed in Wind Walker were buying Wii's in droves for a return of photo realistic link in a gritty dark adventure.
The release timing also is important. When TP launched the global economy was far stronger but after 2008 the global downturn has had an effect on video game sales. Skyward Sword has done pretty well considering this economic crisis.
Toss in the fact that motion controls are old now, even Motion+ wasn't enough to make AS the same revolution that TP was.
-JC7
"In God We Trust - In Games We Play " - Joel Reimer
