Yes, it's stretching the definition. The fact that consumers are buying plenty of things that will wear out soon is not evidence of planned obsolescence. It is evidence that consumers prefer those products over those that last longer (probably because they are cheaper).
Do people really prefer cheaper things? Often people can only afford cheaper things, and don't prefer them over well-built things. I buy cheap things and often would prefer a more expensive thing.
I can further unravel the logic of my two statements if you prefer, but it's probably annoying.
You are right, I was not using the colloquial sense of the word. I was using it to mean what people choose to purchase under price/budget constraints[0].
