I to am not a tribologist an only go buy what I garner from people with more experience and smarter than I am. The way it was explained to me is you want enough to last through to the next oil change. When the moly adheres to the surface of the metal and you get the friction of metal to metal the moly does wear away and a new particle moves in to take its place. This is on a very small scale and you are correct that it does not take that much but you want enough get through to the next oil change. From talking to some mechanic friends who have use it they tell me that the 100-200 ppm that you find in Mobile 1 does help but is not enough to make it from one oil change to another especially in a motorcycle where your engine rpms are twice that what you find in a car.
Also as I think we all know the synthetic oils ability to lubricate will go a lot further than dino oil. The problem starts when all the other additives for viscosity, detergent, antifoaming etc. get used up way before the oil really breaks down. I used to use Mobile 1 extended which adds extra additives so it can go longer but I can't find it anymore.
"If it ain't broke take it apart and make it work better"