I feel like planned obsolescence is much more common that we initially think. For example, on the phone market, battery lasts on day out of the box. If we consider the battery losing .05% of its total charge after each charge/decharge cycle, after 2 years of constant use, it already lost 30% of its total charge. Yet, despite everyone being annoyed with having to charge their phones at least everyday, apple, samsung and others keep making phones that last a single day on a charge. They make their phones bigger, bulkier, faster, but nothing on the battery side (I think there was an article linked here where the author claimed he cracked the apple battery equation and his thought was "they make it last a day, not more not less)". And we can add to that prohibitive repair price and refusal to support older platforms, even though it's often just a cross compilation away.

I get it that it's probably better for any company out there to sell new devices rather than support old ones for free. It just that the "I doubt planned obsolescence is common" strikes me as a bit naive