I see what you mean. When we came 2nd under RB, that was a definite title challenge. As odd as this may sound, there were times when we ended up 3rd or 4th that felt more like a challenge than 2nd under GH.
The 2nd place finish under GH wasn't really a challenge. As far as I can remember, it was mainly between Arsenal & Man Ure. Arsenal ran away with it and then right at the end, we pipped United for the 2nd spot.
Under Rafa, it was totally different. We were top of the league at Christmas, then blew it with a load of draws in the new year, but came back very strongly at the end and almost caught them - but didn't (for various reasons too painful to go into!).