Wouldn't be so sure of that, Humphrey had little interest in being President and bar the war issue, was fond of RFK, while for Bobby it was the opposite, I doubt he'd have taken the VP spot. If Daley's Chicago political machine got running as it was bound to, backing Kennedy, Humphrey would have needed major incentive not to bow out to grass roots (and super-delegate) pressure and his own lack of will. Daley was a kingmaker and I really cant see his influence being broken, even by the LBJ backed "conservative" candidate.
An RFK victory at the Chicago Party Convention also means no anti-war riots which might see Daley's grip on the city and arguably the Democratic Party remain strong.