Brock Lesnar stunned the WWE Universe as he made his shocking return to the Stamford-based promotion on SummerSlam Sunday, after the main-event war between John Cena and Cody Rhodes. He attacked the Last Real Champion, subtly confirming their feud next.Fans had high hopes that The Beast would appear on SmackDown this week and address his attack on Cena, and the two legends would kick off the final chapter in their iconic rivalry.However, the entire trajectory has flipped as not only has John Cena kicked off a new feud against Logan Paul, but his match against the former US Champion has been officially announced for Clash in Paris. Moreover, Brock Lesnar didn't appear on the blue brand, leaving fans confused about the future of the Cena-Lesnar storyline.In this listicle, let's look at three reasons why Brock Lesnar missed the post-SummerSlam edition of SmackDown:#3. WWE is saving the superbout for the bigger stageA match featuring Brock Lesnar and John Cena will indeed be a huge box office spectacle. The response from fans at SummerSlam Sunday, upon The Beast's return and attacking the Last Real Champion, was enough proof of the same.However, there is a massive possibility that the Triple H-led creative is saving the supermatch for a bigger stage. The bout between the Ruthless Aggression legends might feature at Crown Jewel: Perth.#2. Building a new rivalry for Cody RhodesLesnar's return to the World Wrestling Entertainment at The Biggest Party of The Summer affected The American Nightmare's moment and overshadowed him a bit.WWE had to kick off a new storyline for the Undisputed WWE Champion, Cody Rhodes, and they indeed did it on the post-SummerSlam edition of SmackDown as Drew McIntyre snapped on Rhodes in the main event, brutally attacking him in the process.#1. Logan Paul was always planned to face CenaSince the Last Real Champion announced his retirement tour last year, there was wild speculation over his potential opponents, and Logan Paul's name was among the top names.It appears Brock Lesnar may be the final feud for John Cena, and before that, the Stamford-based promotion might have wanted to elevate Logan Paul by putting him against The Cenation Leader.This could be another reason why Lesnar hasn't shown up yet; he might return after WWE Clash in Paris or even be involved in the premium live event in a shocking manner.