I don't get it either, Dan.
It was obvious that VY was going to be a work in progress in the NFL - didn't play in a pro-style offense in college, had/has some mechanics issues with his throwing motion, etc. He took the league by storm as a rookie - largely with his mobility and the ability to make plays with his legs, not his arm.
The league had the entire off season to break down the film and adjust to VY - and they did. When you combine that with the fact that the Titans aren't exactly loaded with playmakers on the offensive side of the ball, a second year slump seemed pretty much inevitable to me.
Now, it will be up to VY and the Titans to make the next adjustment. IMO, they could help him best by getting a few more playmakers on the offense.