He doesn't need it, it would be stupid. 20 and 0 is a perfect number for him to go out on, the moment where him, HBK and HHH are all on the stage with each other is a fitting end to his career and pretty much the only thing on that PPV worthy of being called a "WrestleMania moment", and any Streak match from this point forward is anti-climactic. How do you sell a nearfall at Mania and have people believe it after what they've just seen? I'll admit it, there were certain times in that match...they had me. I was worried Triple H was going to end the Streak when HBK and HHH did the SCM/Pedigree combo. But after kicking out of everything he did at this Mania, it's done. He CAN'T lose. They couldn't convince me that Brock Lesnar and The Rock in a handicap match were a threat to the Streak after what we've seen this year.
I agree with this 100% however, keep in mind that the age group and fans that the WWE cater to right now aren't as smart as we are and don't exactly have that well of a memory, I mean let's face it the WWE fans have a memory of a goldfish. At Mania 27 it was built around HHH/Taker being once in a lifetime but they've already met at Wrestlemania before back at 17. I can still see them doing Taker at more Mania's and milking out a Cena match, even though it may not seem worthy for the streak kayfabe wise the fans will be happy to see it cause they aren't going to sit there and think to themselves at the age of 10 or so - "Hey, Taker beat HHH and Shawn twice and in a Cage... what can Cena do that they can't?" it's jsut not something that they'll do. Kids kayfabe wise don't question the WWE, we were all young marks like that..