"... but it would still be quite the discovery that car factories are regularly stopping because of a lack of steel ..."

What if you dug deeper and found that the steel-lacking factories were the ones which made the worst cars ?

I think that's the default analogy you should be making when you see cells "stopping".

This idea that cells that stop processing, or that undergo apoptosis (cell death) or are incapacitated by free-radical damage / oxidation should be "saved" is probably a mistaken one.

It's probably a much better outcome that they die.