FWIW,  Cam failures come in two basic varieties.  Catastrophic where the cam
drive pulley/gear or other part of the cam actually fractures and wear
related where the hardened bearing or cam face surface erodes and wears
away.

Ignoring the previous as it is generally an undetectable metallurgical
fracture until after it occurs, the wear mechanism is pretty well known.
The faces and bearing surfaces are polished and hardened.  If the hardening
develops a pit or wear mark due to loss of lubrication it quickly wears the
cam follower which in turn causes more wear on the cam.

Things don't get better from there.  There will be no indication of oil
pressure loss or any other fault until the motor starts to underperform as
the timing and lift characteristics change the performance of that
particular cylinder.

Replacement of the camshaft or rewelding regrinding is the only remedy.
Inspect the cam bearing journals for wear and replace as necessary when you
replace the cam.  Change the oil at 300mi and 600mi after the change.

cheers,

pensioner