This is quite insightful. I never thought of it this way but I think you are correct. If I could rephrase it a bit more clinically, the signaling of fitness (

This is quite insightful. I never thought of it this way but I think you are correct. If I could rephrase it a bit more clinically, the signaling of fitness (wealth, social status, etc) is important to the human mating rituals. And diamonds are integral to that in a some cultures. That underlying need is probably innate will not change. Therefore, as you said, you can't just say "NO", it needs to be replaced with something else.