That may be true, but good closers blow 7 or 8 games a year. Kimbrel only blew 4 last year. Are you willing to lose 3 or 4 more games because of the downgrade?
Kimbrel is 66 for 72 in save opportunities since he got to Boston. That is 91.6%. Look at the numbers from so called "good" closers from last year
Colome 88%
Osuna 79.5%
Knebel 86.7%
Allen 88%
Herrera 83.8%
Say an elite closer saves 90% and a good closer saves 84%. Assuming 50 chances, you are going to blow 3 more games with a "good" closer than you are with an elite one. These are wins that turn into losses or wins later on. Also, a "good" closer on the open market is worth over $10 mil per year. Heck, good middle relief guys are getting $8 mil a year. Kimbrel may end up being 8 or 9 mil more than a good closer per year, but he also comes with 3 more locked down wins. If that worth it?