I agree that the general population sees the ones dug out of the ground as "real" right now. I think the story being paid for is the DeBeers story though, of diamonds and marriage being inseperable, I don't think many people consider much where they came from, or consider the "rare thing dug up out of the ground" part of it particularly important in itself.

I guess I'm splitting hairs, yes there is definitely a cultural hangup about mined diamonds being "real" and made diamonds being imitations, fake, whatever. I just don't think many people care that much about the actual backstory, they just want a 'real' one. As such I think the synthetic diamond industry has a bit of an uphill struggle on its hands, but not an unwinnable one if they can convince people that theirs are 'real' too.

And to my (very literalist in many respects) mind, they are.

(edit - I will add that I have gone out of my way to source lab-created stones and silver settings to make jewellery for my partner in the past, so far mostly using star-sapphires, and she seems to have loved them. I find the idea of lab-recreated gems pretty fascinating, and I think that enthusiasm helped.)