If you have a product that's been in the market for a while and it looks like it's meeting service life expectations you start looking at it trying to find ways to save money by substituting cheaper parts. You swap out metal gears for plastic gears, for instance.
If these parts have a shorter service life, but the service life is still longer than the warranty, then maybe that's a win in two ways for the manufacturer.
If you have a product that's been in the market for a while and it looks like it's meeting service life expectations you start looking at it trying to find ways to save money by substituting cheaper parts. You swap out metal gears for plastic gears, for instance.
If these parts have a shorter service life, but the service life is still longer than the warranty, then maybe that's a win in two ways for the manufacturer.