Isn't the point of a diamond its beauty in the eye of the beholder? If I had a big diamond I would definitely want the cheapest one possible with a visual aesthetic I like. Fortunately, my wife and I don't like diamonds and we have purple sapphires in our wedding bands.
At any rate, at least we can rest assured in the knowledge that if it weighs the same as a duck it is definitely a witch.
With all the problems of natural diamonds, I would prefer a lab-grown diamond...
Women's cultural conditioning and arguably human nature. It being a completely unnecessary but very costly sacrifice to the man is the feature, not a bug. It doesn't need to have intrinsic value, all that matters is that it is an accurate signal of excess wealth.
There are those (like you and your wife) who see past this, which is great, and I hope this trend continues.
I don't know why the equality crowd isn't vehemently against a high and essential cost from one gender to another, nearly unilaterally. (Well, cynically they like it because it affects mostly men, and indeed works as an accurate signal of affluence.) But it would be great, for causes like income equality and the wage gap, if this could be turned symbolic, instead of an actual costly sacrifice which is entirely a burden on men.
They just make do with wedding bands and wear nothing before the ceremony. Seems like the engagement ring is a phenomenon very specific to some western countries.
You might as well ask why people buy first issue Superman Number 1 comics and not a reprint? Same shit pictures right?