They also have an incentive to make it last a long time so you're a loyal customer. Loyalty is extremely important if you only purchase a half dozen of something your entire life. Guess which incentive is stronger?

As a corollary, there is a big difference between being incentivized to do something and simply not being incentivized to do the opposite. The average full-size refrigerator lifespan is 17 years. The fact that Maytag doesn't spend millions of dollars developing a fridge that can last 30 years doesn't mean they're incentivized to make a shitty fridge, it just means people don't care enough about years 18-30 that they're willing to pay what it would cost to get that fridge.