If you want moissanite or something else, or dream of asteroid mining to flood the market on earth, that has nothing to do with anybody else in the market for diamonds.
Like if you buy a gold ring, I suspect its cost will be pretty related to the base price of commodity gold, the labor involved in creating it, and a reasonable markup for the company to survive. But it is too commoditizatized for it to have the super high prices diamonds have. Knowing that diamonds are horribly overpriced will reduce some people's desire to actually buy one. So telling people this helps save people money.
> I think the understanding that they are not rare and that the price is entirely an extortionary corporate fiction to collect huge profits will influence one's desire to pay the high price.
That's like telling people their Gucci bag actually costs $100 to manufacture and thinking it will make them stop buying them. People do things to signal social status. It's never been a rational thing so rationality isn't going to fix it.
If we flood the market with diamonds people will find the next status symbol to cling on to. You can try to stop it at gun point like the Soviets/Chinese did but that still never stopped the remaining few with status from engaging in it (see NK today).
Humans are just flawed biology who do dumb stuff and there will always be another person who will give it to them in exchange for their money and another person to desire what they now have.