[Bartweiss]

The other point is that you don't want to over-engineer any single part. Getting a 10,000 hour lifespan out of the motor is useless if the chuck cracks in 2,000 hours and the thing gets thrown away. Ideally you'd have the entire thing fall apart at once.

But, of course, failures are statistical. Worsening the quality of the most over-engineered part is usually beneficial, since in most cases you're paying for nothing, but occasionally that'll still be the part that gives out. So you come out ahead by making a more cost-effective product even while failure rates rise.

Of course, that's where the article's point about insufficient competition comes in... Standardizing quality throughout the device is sensible, but if those savings aren't passed to the consumer then they're losing money.