All of your DVR recordings of Raw right now featuring this build to Daniel Bryan against John Cena for the title will one day be cherished clips on an amazing career DVD.
Torch, candle, flag―whatever it is you pass, the passing is about to take place. Cena isn't going anywhere. His days in WWE are far from over. However, his days of being the sole guy relied upon for the future are about done.
You can't force it (see failed babyface attempt with Ryback) and you can't rush it (see early career of Randy Orton). Bryan has been neither forced nor rushed; in fact, with him it would be accurate to say, better to be a day later than a day early. Fans have been gathering for the past two years, as no other bandwagon has seen this kind of steady increase.
CM Punk got a huge surge in momentum from his bandwagon his after his famous speech in 2011. Punk is great, but I also don't expect him to be an active wrestler past 2015. He's a good attraction while you have him, but he doesn't have 10 more years in him.
Every week, Bryan gains new fans who start to believe, understand and care about him. It's for all these reasons with Bryan that his feud with Cena must continue past SummerSlam. To properly tell this story, it can't all be done and effectively culminated in one pay-per-view match. It would be too much for the audience to absorb and wouldn't do justice to Bryan's reign as a top guy.
Bryan is on the same path Shawn Michaels was in early 1996. The crowd is solidly behind him as he moves down the road that leads straight to the WWE Championship. When Michaels beat Bret Hart, it was a similar situation. Hart had been the man in WWE and while he wasn't done with WWE yet, it was time to relieve the burden of the company from his shoulders.
Hart and Michaels went 62 minutes at WrestleMania 12 in an Iron Man match that was forced into overtime. This all happened on one night. This can't happen today. Not because Bryan or Cena can't go 62 minutes, but because the WWE audience can't. Not today. Not anymore.
Hart and Michaels felt epic for the 62 minutes in one night. Bryan and Cena need that epic feel to take place over the course of several months. This way, when it all the dust settles, the triumph and passing of the torch will come at the appropriate time.
We have Bryan challenging Cena with the WWE alluding to the angle that Vince McMahon doesn't like Bryan. Add the Bella's relationship (which I'm sure will be used) and Orton lurking around with the briefcase, and you have a lot of elements to use that need several months to ultimately sell Bryan as the new bearded face of WWE.