Lost my cam

Purely for discussion's sake because I personally don't have any experience with a cam wiping out on me but I have had my share of problems as most know. Also I've never had A oil pump 100% completely apart so I don't know how close the tolerances are. course I put them in brand new. But I'm thinking this cam didn't just wipe out in a matter of minutes but it took quite some time to slowly and I mean very slowly work this came down to a point to where it's not functioning. In that case I would think that there was no big massive rush of metal particles, but yet it slow gradual loss of Cam?