Not sure about Bush being any sort of shoe-in. A two-term Rep., UN Ambassador for the disgraced POTUS, and former CIA Director and RNC Chair is quite a resume but hardly any of these positions are elected or are ever springboards to the presidency.
IMO, Bush would seem strong in the early primaries and then burn out.
I think the race would come down to John Connally and Howard Baker, with Gerald Ford being seen as a distinct possibility throughout.
Baker would be the centrist establishment pick and Connally would be an insurgent conservative who would be less overwhelmingly popular with the party compared to Reagan due to being a former Democratic Governor and his very close ties to Nixon (closer than Bush). The difference between Bush failing and Connally potentially succeeding is there was a better alternative to Bush in terms of centrists liked by the establishment (Baker) and tbe PoD for this is the better conservative alternative to Connally (Reagan) is dead.
Ford jumping in the race would really shake things up, and he just might. If he does, I’d expect his VP pick to be the 1984 heir apparent and my personal favorite for that role is Larry Pressler, giving us a centrist, ideologically consistent GOP President alive and active to this day.
Larry Pressler presiding over those good times would make him quite a voice and I have a feeling he’d seek public office again unless he has a downright tragic (two) term(s).