It was not planned depreciation, as many chips were failing even before 2 years and this impacted not only PC Builders and Gamers, but also some server infra providers too.
This was simply poor design, it took Intel ages to really figure out what went wrong and "resolve" it.
It cost them far more than it made.
They didn't replace all the chips like with the FDIV bug though. What did it cost them? Only reputation?