"The WWE Championship match should be the main event every night. Not having it in the main event takes away the prestige of the title!"
How many times have writers written this?
While it is a perfectly valid point, keeping this storyline out of the main-event scene means avoiding the baggage that comes with being a part of the main event: John Cena, a load of old men and too much talking. Let us look at these three points one by one:
First, if John Cena is in your storyline, fans will simply be watching in anticipation of Cena's likely emergence as victor at the end. Cena is a very talented man, but over-exposure has made him a less exciting man to watch.
He is also responsible for maintaining WWE's children's audience. While he does this very well, it means he is not an ideal candidate for a more interesting and complex storyline such as this one. With other child-favourite Rey Mysterio still out of action, Cena has had to perform this role more than usual.
Secondly, old men? Yes, WWE is full of them at main event level.
John Cena is no spring chicken, but compare him to the men currently involved in the main storyline on Raw: Paul Heyman, Triple H, John Laurinaitis and Brock Lesnar. Vince McMahon recently came back to Raw, and many fans theorise that Shawn Michaels' upcoming appearances will also be used to incorporate him into this storyline.
Lastly, too much talking. WWE's main storylines always involve a lot of lengthy promos. This is why old men like Vince can still be involved, and it detracts from the actual wrestling.
By being a sub-main event storyline, Kane, Daniel Bryan, AJ Lee and CM Punk can avoid all this and just get on with business. Additionally, as many of WWE's elite only show up on Raw, this storyline has been allowed more time to build on SmackDown!.