Cena and Orton

So, between them Cena and Orton have held:

19 WWE Championships, 6 World Heavyweight Champions, 1 Intercontinental
Championship, 3 United States Championships, 2 WWE Tag team Championships, 3
World Tag team Championships, and won 3 Royal Rumbles. The FIRST of those
titles was won in December 2003. Cena is still 36, Orton only 33.

The obvious question…if YOU were booking WWE, would you keep going with what
works(these two guys), or push someone new? It's clear that no one else can
really do the business they can(including Daniel Bryan). But if something
happened to one or both of Cena and/or Orton, what could they realistically
do?

To be fair, you forgot the 2 Money in the Bank wins between them.
And nothing will ever happen to them, because in WWE-world everything good that happens remains that way forever and no one ever needs to think ahead and have contingency plans.