Ratings last week actually weren't that good for a show featuring the Rock as his segment even lost viewers according to the Nielsen ratings. This week was a different story because it had the lead in of the Royal Rumble PPV which was covered by mainstream media and is the official kick off for the "road to wrestlemania." As for Jericho just taking a spot, you could argue that the Rock took someone's main event spot. Annually, the Royal Rumble is the one PPV where the heavyweight title is not the main selling point of the show. The WWE tends to give new and/or rising talent heavyweight title shots at this PPV in order to test the waters.
For example, 2012 = Dolph Ziggler vs. CM Punk, 2011 = Dolph Ziggler had his first title shot which was more unexpected, 2010 = Sheamus was actually the WWE Champion for this month shortly after his main roster debut, 2009 & 2008 = Jeff Hardy in the heavyweight title picture, 2007 = Umaga and Mr. Kennedy in the heavyweight title matches. I could keep on going...
As for the high quality talent pool shrinking, I wasn't aiming that at the quality of the in ring performances, but the personalities and gimmicks that can transcend age groups, male/female interest, and enter the mainstream. I think they could have done it with the Miz a few years ago, but they just didn't know what to do with him after he lost the belt. As boring as he was, Boobly Lindsey could have done it. Kurt Angle was the guy before he went off the deep end and entered obscurity in TNA. Guys like CM Punk, Daniel Bryan, Sheamus, ADR and Ziggler will always appeal to the typical wrestling fan, but will never draw those from the fringe. Also what chappers wrote does apply, every face and heel that gives a promo these days sounds like its coming from one failed scripted reality show writer making it harder for an individual to stand out. If you notice, most of the Rock's biggest pops are after he stretches the TV-PG limits.
I believe there are only two potential major paydays left for a major Wrestlemania event, Stone Cold Steve Austin vs. CM Punk and Stone Cold Steve Austin vs. John Cena. I'm not even sure those two are physically possible either. I also wouldn't be surprised if the new Lesnar deal has him penciled in for the main event next year. After that, will the Wrestlemania Main Event become "just another PPV" in a stadium?