I have never denied this. there is a difference between possibly finding ways to cheap out successfully at closer, and saying a player who's one of the most consistently effective at his position, a very dependable closer who has always been able to take the innings and make the saves over a 11 year career and shows no real signs of slowing down, is overpaid when he makes half what the best starting position players and/or starting pitchers make.
Make no mistake, a player of similar prominence in any starting position on the field would make more than 12-15M. I wouldn't say he's overpaid or underpaid. I would say he's paid like something that's actually a very rare object in professional baseball -- a durable professional closer that's been able to stay in the field as a closer without major injury,loss of command, or just plain getting figured out by hitters, for over a decade.
Closers don't tend to get paid because closers don't tend to be as durable as Pap has been. Closers that are that durable, get paid. Prove me wrong.