All I can say is that I set up my bikes properly and they work. The idea that things with closer tolerances don't work as well or go out of adjustment more frequently, Because of closer tolerances, defies logic. Every car on the road today has engine tolerances Much closer than fifty years ago ... and last two to three times as long.
Anyway ... whatever. I have 7,8,9,10, and 11-speed, and I don't have problems with any of them. Sorry 'bout your problems, guys.