It's the unfortunate reason that marketing departments will never go away: When done well, it's extremely effective.
"Here's a thing you have never seen before, nor have you ever needed it. Well this thing is now the most important thing you can possibly want, and you will do whatever we think you should do in order to get it."
"Oh. Ok then."
You could argue that DeBeers has pulled off the greatest marketing campaign in the history of civilization. They convinced people that they needed this (useless) product. They developed an atmosphere of peer pressure that subtly urges the civilized world that they must purchase their product or be seen as skinflints who don't love their partners. They convinced people that their product is very valuable, worth a lot of money and retains that value even as there was never any evidence that it was (or is) true.
Perhaps the best part was getting an entire society to believe that there was a benchmark amount to spend on the product - two months' salary for an engagement ring.
I have always been impressed with their ability to pull off this Jedi mind trick on such a large number of people and continue to do so for many decades. It's simply brilliant.
One of the greatest.
I can think of another one that's even larger and more pervasive, but there are plenty of threads on that subject right now.
And hey, I love diamonds too. Such an exceptionally stable crystalline structure, such excellent hardness and thermal conductivity. It's a damn fine material. Since artificial ones can be made more perfectly than natural ones, I just don't see much need for the latter.
"Here's one that was made by
science, in a lab, in a high-tech pressure cooker, built up a layer of atoms at a time. This one was buried under a lot of dirt, and was likely dug up by mistreated third-world laborers." Ooh, yeah, I want the second one.