And that is true. I even mentioned it earlier today.
But that diesn't mean you go all in for a closer. Bullpens run 7 to 8 pitchers deep these days, and addressing a bullpen solely by trying to improve a ninth inning specialist is not necessarily the best way to go, even with the trickle down effect (of moving Koji to earlier innings). And as the objections to acquiring Kimbrel were largely the impact it had on the farm system and the overall cost and impact on team payroll, this was overkill, to be kind. A bit like fishing with dynamite, except in this case it substituting the TNT with C-4.
Could the Sox have acquired other bullpen arms who were not among the highest paid in the game and without giving up farm talent (needed to maintain an economic balance on the team) that off-season? DD did try that route as well, and while he failed miserably, the reasons why were not on him. (I liked the deals that brought Thornburg and Smith to the Sox, despite neither working out.)
But instead of Kimbrel, there were other relievers the Sox could have grabbed for a lot less while leaving Koji in the closer role.
My observations on pitcher acquisition is teams are better off trading for starters and signing closers. Even the best closers who get the bigger contract at least only get them for shorter terms....