Failed Oil Pump on 1996 Chevrolet Lumina

The car stalled while driving. Repair shop says there's no oil pressure so oil pump must have failed and needs replacing. $750. Q: How common is oil pump failure and can it be clogged oil galleries? The oil is very dirty, I don't know when my son last changed it.

Asked by for the 1996 Chevrolet Lumina
it is not a common failure but not changing the oil can cause all kinds of failures.
with dirty oil, any passage could be clogged with sludge

1 more answer
Could it cause zero oil pressure? And can it be flushed out instead of paying $750 plus? They may find other things wrong after replacing it?