They don't take 5 years to develop, they take 3 to 4 years.

Skyward sword was an exception because it was already 3 years into development when they decided to implement motion +, so they had to rework a lot of stuff.

Zelda U doesn't have a release date yet. If it releases first half of 2016 it will have been 4 and a half years, even though they needed extra time with hd development.