how complicated can it be to build an aperture ring?

For Leica, apparently very complicated:

Not one, but TWO APO 75/2 Summicron duds (note position of aperture ring!)

I've used dozens of Nikon lenses, which all have coupling levers in there too - and the only time I've had an aperture diaphragm fail was when using a 1960s pre-AI 55/1.2 SC on a D2H. At 8fps. That's understandable. But for aperture diaphragms to fail on a rangefinder lens, where the thing doesn't even open and close for every shot...now that's disappointing.

Incidentally, my 50 lux issue still isn't resolved yet. I've very much lost all inspiration or desire to photograph of late. Sigh.