I still don't think Bergevin cares about paying Subban what he's worth. To me that was the whole point of the bridge contract - I'm sure Bergevin knows he could have caved and signed Subban to a discount for a longer term, but I don't think his goal is to nickel-and-dime his players. I think he's more than okay with saying, "we don't have a problem paying you what you're worth if you accomplish the goals we set out for you". Maybe it'll cause him cap headaches, but I think he values the good will and the culture it creates over a million or so bucks in cap space.
At least, that's what I believe his philosophy to be. Whether you agree with it or not is another thing entirely, but I think it's at least respectable (if maybe not practical from the point of view of the cap).