Jericho is moaning about the fans who keep expecting him to stay in the ring (Hence the Methuselah comment) I'm guessing, and Regal is obviously a bit offended by that, 'putting him in his place' so to speak.
I think Regal is getting at the point that Jericho shouldn't be so full of himself, because whenever Jericho comes and goes he makes a massive deal out of himself, and for someone like Regal who bleeds the wrestling business, it's somewhat offensive I'de assume.
Of course, that's just how I perceive it to be.
EDIT: Maybe Regal just thinks he should be more grateful. I think the problem is that Jericho wanted to be a Rock star all of his life, and now he has both, and Regal probably thinks it's a bit selfish to be in his position and be complaining that all of his fans get pissed when he comes and goes willy-nilly. It's not Jericho's fault, but he shouldn't be whining whenever fans want him back.
Of course, 99% of this is probably just to get Heat ahead of tonight.
Any idea what the "Perhaps I need to invent some new stuff you can steal from me!" comment was in regards to?