I think that's where the problem lies. MC mechanics tend to over think these simple machines, and never really grasp the very few basic needs these "scoots" have.
They run on Non adjustable belts that must be EXACTLY right. 1mm makes a huge difference.
Rollers control the engine. Not the other way around.
1/8th of a turn in either direction on a carb adjustment means run/no run.
Very simple concept that are overlooked.
You're absolutely right. I think that another thing that comes into play is the disdain that most motorcycle mechanics have for the scooter. At our local bike shop (a Yamaha dealer), they refuse to work on any scooter that isn't Yamaha, and the mechanics are pretty clueless on top of that. I went in one time and asked a question about a variator, and the mechanic looked at me and said "what's a variator?" The sad part is, they also work on snow mobiles there, so for him to not know what a variator is, is laughable. After I explained to him what it was he said "Oh, that's what that's called?" and then told me that they don't do that kind of work there (wanted to change the rollers and didn't have the tools myself to do it).