I used to live next door to a lubrication engineer who worked for a high tech company specialising in harsh environments. He described MoS2 particles as 'the size of the ones in cigarette smoke' and they pass through filters like a mini going through Dartmouth tunnel. The difference is that normal combustion products (mostly acids) will stay in the oil and be neutralised by additives in the oil, Moly is designed to stick to metals, not the filter medium.
It is an extreme pressure boundary lubricant - the disulphide bit is attracted to metal and the molybdenum bit faces outwards and the plates slide over each other with extremely low friction, and when the oil has drained out of bearings they stay behind and are there during those first crucial seconds when the engine starts and there is no oil there to form a barrier between sliding metal faces.
I have done very high mileages in cars and have always used Moly, never adjusted tappets and never a spanner on engine or transmission.
I agree some oil additives are like snake oil, Moly is a well proven and widely used lubricant in industry when nothing else will stand the pace.