This is like asking “why are humans always human?”
I think each of us becomes very comfortable with the people, places, and things in our world. We may contemplate a change. But we know what we have, and even though it might not be the best, we live with it.
People hold onto stocks too long and sell at a loss. People think about divorcing their spouse for years before it happens. Marketing is no different. We’re used to it. We’ve always done it that way. It’s uncomfortable to change.