Managers would read papers about the CMM and declare that they wanted to be a Level 5 organization, causing insane amounts of busywork and document generation and overall grief to realize that their underlying business processes were hopelessly in the way of any positive change.
So then the goal went from "Level 5 or Bust!" to "Okay, let's try to get to 3" and then later "Um, can we make Level 2?" Then everyone just gave up. There were only a handful of shops that ever made 5 and stayed there, the Space Shuttle engineers being the most famous example[2].
[1] https://en.wikipedia.org/wiki/Capability_Maturity_Model
[2] https://www.fastcompany.com/28121/they-write-right-stuff