Because for every 1 DH in Manufacturing, there are “X” SLS and “Y” senior engineers / coordinators / planners / leads, etc.
Where 1 < X << Y
So if the company is unable to create some form of perceived “upward mobility” for these “Y” masses (even after they have been working for more than 10 years and hovering at CL24/25 levels), then there will be gross morale issues that could result to even more attrition and anarchy!
So then: give these marginalised folks some peanut dust, to assume RL positions - and hopefully, appease their not-so-high career expectations, and to continue to serve until another opening becomes available.
If one were to attend the annual PA exercises, you will realise the sheer numbers of “Y” who are stuck at CL24/25 - some for more than 8-10 years!!
The same also applies to the substantial number of senior non-supervisor CL27s, who just cannot break the glass barrier, to be promoted to CL28/29 - given that the latter is for a few designated positions only.
To break these 2 glass barriers, new employees will need to score high in PA rankings from the get go.
You wait 5 years later to do same and your lagged career projection chart will unlikely bring you up to CL29 (not to mention Executive level) before the time you retire!