There's a difference here. Cena didn't come out and say that WrestleMania main events are only for people who have earned their spot, and him winning at the Royal Rumble is unfair to those who worked for months to be in it, so he's giving up his title match. He made it clear he didn't want to wait until WrestleMania to face Orton and get back the title, Orton refused and chose to defend it at No Way Out, Cena gets screwed over. At the same time, since there's no challenger for the WWE Championship at WrestleMania, they have an EC match at No Way Out to determine who it is. Triple H wins, but Cena wants another crack at Orton so he faces him again to be inserted into the title match at Mania. And throughout all that, Triple H was annoyed that his one-on-one match was taken away from him.
I don't know what WWE's plans were for WrestleMania before Cena got hurt, but after he got hurt, I'm assuming Triple H was going to face Orton. Then Cena came back, and there was no chance in hell he wasn't going to be in the title match. At the same time, Triple H was supposed to be in the title match a year before, and it's obvious he was going to face Orton, so a triple threat match was the best compromise. It gave us a match we hadn't seen before and everything lined up story-wise.
I don't know where they're going with this current situation, but unlike Cena, Cody's spot in the title match isn't guaranteed. There's a very good chance they'll do Rock/Roman and nothing else to it. A triple threat is their best option right now and it would make up for what they didn't do in 2013, but I don't see them doing that.