planned obsolescence sounds abstract until you look at the examples.
in the 1920s, major light bulb companies were accused of agreeing to keep bulb life around 1,000 hours even though longer lasting bulbs were possible.
decades later, apple got criticized for slowing older iphones as their batteries aged. apple said it was meant to prevent unexpected shutdowns, but the bigger issue was that users were not clearly told. after the backlash, they apologized, lowered battery replacement prices for a while, and added battery health controls.