User blog comment:Dxf289/Is it just me.../@comment-37591941-20190125054933/@comment-37591941-20190126061023

Well...It also dpends upon if they have the capability or not or if they want to or not. LIke Kurobee wanted to be a black smith, Shuna wanted to help in production & Hakurou...became a teacher but I believe that they did get stronger (i.e., increase in EP) but not just too much. Even Gobuta must have gotten stronger since he had an EP:24,000 (which for a Hobgoblin is pretty impressive) when Rimuru evolved into a Demon Lord.

Therefore I think it also depends on the field in which they work & also their titles which determine their evolution & them getting stronger.