Unless Vance really falls hard on his face, I don't think RDS has much of a chance. Very competent governor, but he lacks charisma that Vance seems to have in spades. I don't think SecDef or whatever Trump might do to "level the playing field" for RDS would move the needle for him defeating Vance for the nomination if Vance decides he wants it. For their party to keep the WH after Trump, it will require a very successful second Trump admin, which would Make Vance even harder to push aside in a primary.
As a sideline observer to the political parties, it's amazing how reliably the (R)'s of the last decade or two become their own worst enemies as soon as the balance of power tips in their favor, with spurned presidential hopefuls of the past leading the charge. Hopefully that thread is mostly about extrapolating past (R) behavior to kill time and fill in gaps until we see what really happens. As a competent guy, it seems like the (R)s would want to keep RDS actively on their team, but the subtext seems to be he wants the top job or he'll do what he can to burn it all down. Not good.