I think Pietro is an idiot for leaving St. Louis over such a small amount of money.
You take away the extra year and add in the higher AAV and no state tax, and its six of one and half a dozen of the other.
Then you throw away the goodwill of being the captain of the only cup-winning team in the 50+ year history of the franchise, married to a home-town girl and raising a young family in the city where he was drafted as a teenager and it isn't even close. Money can't buy those things. They have value and he threw them all away.
It was never about the money. With hockey players at the top of the game, it's about what the money says about how you're respected / valued in the league and by the team.
That respect element is why AP is no longer a member of the Blues. He believed (and rightfully so) that he deserved a full NMC and substantial bonus money. Doug Armstrong doesn't do that, and while he indicated willingness to do some of it, it was never going to be a hard-stop, full NMC for all 7-8 years.
It's knowing that team and player had completely inflexible positions in this regard, that caused Armstrong to go out and get Faulk, which in turn caused even more feeling of disrespect by AP.