Absolutely true.
Last year for the Sox, the bullpen threw 587 innings, of which Kimbrel only pitched 62.
I have faith that Barnes can handle the closer role; he has improved every year and he is certainly capoable lready. But it's the handling of the other 525 IP that bother me. I lack the faith in Braiser that many have. (He was in Japan for a reason, folks.) Hembree is OK. Thornburg and Smith need to recover. Workman is about the bottom of acceptability. Johnson is barely a major leaguer.
On the bright side, apparently there is something to this Colten Brewer fellow. Domingo Tapia had one of the most dominant pitches in the minors not too long ago. Meijia was a former Met top prospect and good closer. And Lakins, Feltman and Poyner are available.
And there are still penty of free agent pitchers besides Kimbrel. Nick Vincent, Aaron Loup, Tyler Clippard, Jake Diekman, and Ryan Madson would all be potential improvements for the Sox...