A friend got proposed a couple of months ago and her ring is ~40k USD. In my opinion, that's crazy since they're spending ~30k CAD on their wedding.
My partner also mentioned that she'd like a wedding ring of the same calibre since according to her - diamond ring is how much love / value / worth I hold for her. Furthermore, a significant group of middle/upper-middle class want naturally occurring diamonds (because they're "real") over lab produced ones (not because of the quality, but because of the tag associated with and the societal group pressure). Furthermore, the same group also hate moissanite because it's not diamond.
It's irrational, marketing and conditioning all they way down.
Hopefully, stuff like this forces lab grown diamonds to the mainstream culture so that we can finally get rid of that mentality.