I think Dave only wanted to keep going until Jay was finally done for good. That was the only “win” he could hope for. So the 2015 retirement is quite possible.
Except … CBS is making really good money on the show. They have no one else that would do as well in that slot so they are going to really want to keep him around.
Note that WWP has been really good for CBS and vice versa. The money they made off of Everybody Loves Raymond is immense. WWP also co-owns The Late Late Show.
Dave is incredibly loyal. He always felt bad about bumping Tom Snyder at NBC so he brought him in as host of The Late Late Show to make up for that. He would go bananas if Ferguson doesn’t get the 11:35 slot when he leaves. CBS would have to nearly start over in both time slots, new hosts, new production companies, etc.
I think they would give Ferguson a try. When he “does a Conan”, then WWP would agree to someone else. But they would require a trial period first. So the interesting question would be who would get the 12:35 slot? That person would be poised to take over for Ferguson at 11:35.
And I like Geoff Peterson. Best talk show sidekick ever.