Its in the big ends, the mains, the small ends, the bores, valves, all the other bearings, its in the grearbox, clutch.. and all over the place. Would you want to keep this engine after this had happened? May as well just put grinding paste in it
That’s not really the way it works with surface wear as the particles are microscopic. Cam wear has been an issue on many cars and bike engines historically ( Ducati 9 series and Honda vf’s for example )and it never had a knock on affect on the engine as a whole. Component break up, as in a gear tooth, sprag failure, spun shell etc is what does the damage as the particles are big enough to damage the surface elsewhere.
Back in the days of Fords Ohc engines which suffered spray bar issues, most engines would go through several cam failures in their lifetime without issue.