In an ideal world with infinite competition and perfect knowledge about competing products, perhaps you'd be right. But in the real world where we live, it happens all the time.
Start by reading about the Phoebus cartel: https://spectrum.ieee.org/tech-history/dawn-of-electronics/t...
I remember my first electric razor. It failed after a couple of years, so I took it apart to find out why. I discovered that the electrical contacts to the motor were just little pieces of graphite, and when they wore down to nothing the razor was finished. Definitely planned obsolescence in action!
