"BTO model and minimal stocks to blame"
Yes and no.
BTO and minimal stocks would be OK, if there was resilience in the supply chain.
But somehow no one in authority seems to have noticed that the hard drive industry had somehow ended up with critical parts of the process all in the same [low cost labour] place, vulnerable to a geography-related incident, regardless of whose badge was on the eventual hard drive.
Anyone with a clue would have understood the value of dual (or multiple) sourcing in a case like this. Or even just the value of holding a bit of stock (on rotation) to keep high-value customers sweet(er) if there's a hiccup in the supply chain.
But big business doesn't have much of a clue these days. Not at the top anyway.