Bearfoil
Have we had confirmation that wear was present in the stub pipe? You seem to be pretty convinced but I haven't seen a single supporting opinion.
Was the HP/IP structure damaged prior to disc burst?
Most likely scenario remains oil fire leading to disc release and overspeed to burst.
I hesitate to get into speculation about what did happen in a specific incident about which somebody else holds all the cards of evidence knowledge and all I am providing is ignorant speculation.
But from a general sense
Parts not meeting design specifications are prone to early wear-out modes from even normal engine operation including temperatures and vibrations.
Fatigue itself is a wear-out mode to me. Left long enough a crack grows to a point where it opens up and squirts oil.
Failure conditions themselves often lead to cascading collateral damage. Thus a disk failure that doesn't clear the engine in a few miliseconds is sure to mess up its rotor drive shaft and bearings.
Chicken and egg questions are the challenge to the investigator and require postulations, experience, and lots of eyeballing of minute damage to confirm. Any one person is sure to get parts of the scenario wrong, so a team approach with pro and cons works best to establish a meaningful corrective action program.