I know some GUE instructors (living in Belgium, close to the netherlands where there is a lot of enthousiasm for GUE diving). If I look at the Benelux there are only 3-4 instructors, instructing full time, and many more doing it parttime.
In Belgium there are 4 GUE instructors, all Fundies level (with 2 out of those 4 instructors being T2/C2/DPV2/RB80 divers, so real affiniados). They all do it as a parttime job even combining the parttime job with a shop (parttime) selling tech equipment.
In the Netherlands you of course have JP Bresser who is doing a wonderfull job... but I believe it's hard work, because you need to create a need or discover a need just like in any other business. It's not just taking courses and getting the C-card, it's keeping at that level doing exploration-level dives, creating a name, creating courses, using social media, using pics... It's very much virgin territory out there when it comes to GUE. Many people are not able to do that.
Of the 4 Belgian GUE instructors there is only one trying to do the same... he's French speaking and understood that there is a big undiscovered territory in France (CMAS country but also home to some of the most beautiful underwater caves). The others are active in the GUE-BE community and Project Baseline, but are not enough to do it full-time.