There's nothing dense about it. Wrestlers are actors in a live play. Ambrose has been half assing and putting in the most minimal of effort for over a year now because he wasn't the lead. And he's been rewarded for it. If you're running a play or show and a dude is half assing it because he doesn't like the role he's in, that dude usually gets replaced. Not rewarded.
Assuming this was the case ... why was he even put into the Money In The Bank match if he was shytting the bed with no effort and half-assing for so long?
Because he gets reactions, breh. You remember how loud that crowd popped when he beat KO for the IC strap at TLC? That

Last Man Standing match they had at the Rumble? Ambrose during his IC run was probably the most over mother fukker in the WWE, and he is clearly their most over face. He has been for roughly the same amount of time you said he's been half-assing it, breh.