It's a poor analogy because mechanical watches and quartz watches aren't perfect substitutes and aren't purchased for the same reasons. Everybody's phone keeps better time than a watch; absolute accuracy isn't the exclusive measure.

Lab diamonds and mined diamonds are literally identical products.

Now a days the imperfections themselves in the rings are what are valued in natural diamonds.

People from India, thailand, Myanmar etc have not and probably won’t for a very long time abandon a strong preference for natural diamonds, regardless of how much “better” the lab grown ones are.

This is a textbook case of “worse is better”.