No one has said the Sox shouldn't get an experienced closer. Except Dombrowski, who suggested they might try Barnes or Brasier in the role. (This was likely a negotiating tactic.)
But Kimbrel isn't the only closer. And the Sox do have a lot of very key core players with arbitration and free agency pending, And whether you want to admit it or not, there is most definitely a spending limit at some point. Is Kimbrel, who apparently has his targets set at being the highest paid closer ever, really the best use of money? Last time the Sox had a closer who insisted on being the highest paid ever, they moved on as well, And given Papelbon's mediocre performance in Philly, it was the right move...