This was really never true though. Second hand diamonds have been incredibly cheap compared to retail for a long time. Good luck reselling that engagement ring, the pawn shop has a box overflowing with them.

Why don't more people buy diamond rings at pawn shops?

Because of the propaganda campaign from the foaming mfrs: “if you don’t spend a lot do you really love her? What signal are you sending?”

And add to that superstition - "what if this used ring came from a divorce?"

It's easy to fall prey to advertising:

How an Ad Campaign Invented the Diamond Engagement Ring

    In the 1930s, few Americans proposed with the precious stone. Then everything changed.

https://www.theatlantic.com/international/archive/2015/02/ho...

In almost all states, courts will order engagement rings to be returned if the marriage is canceled, and the giver wants it back.

This is likely a legend.

Thats exactly my point: the whole infrastructure of breach of promise, (somewhat) rarity of diamonds etc has been obsolete for decades, almost a century in the US. Any point of an expensive engagement ring has not had practical value in living memory. Just a residual, empty practice.

Every aspect of a wedding outside of the government paperwork is without practical value. It's almost like the practical value isn't the only thing that matters.

Another way of thinking about it is that a wedding itself is a public commitment you’re making in front of witnesses (so in theory harder to back out of — not a bad idea as it provides some hysteresis to overcome transient conflicts).

Meanwhile the government is simply providing some infrastructure as a service to people who want to make such commitments.

The practical value is from the expectation of permanence. This allows you to plan for scale.

Nitpick, not diamond engagement rings. It was valuable engagement rings, it didn't have to be diamonds. The PR men created the diamond specific thing, and gutted the entire meaning of the tradition.

Good point.