Jeb is Next In Line. The Republican Party does not want to win the Presidency. It wants to reward its GOPe stalwarts with the Republican Nomination. That is the epitome of Republican approval. But Republican Establishment types generally do not want to be President any more than GOPe wants a Republican President. Bush Sr. was president despite anything he could do to throw that election. The voters thought he was Reagan redux. Junior only seemed to actually want the job when he saw that he might just squeak through. The rest since Ford- arguably took dives.
You are exactly right. Nomination is a gold watch. Think of Dole.
You could have nominated hard right candidates in 1996 and 2008 and they'd have lost and somebody somewhere would be making the same remarks about them not wanting to win and not wanting a Republican president and about just being nominated being the honor they sought (except those true conservative candidates weren't nominated and probably didn't exist).