There’s precedent for giving a kallah a lot of money for kiddushin, as the bnos beis shamai would only accept kiddushin from several gold dinnarim(i forgot the number).
Granted, a vort is noy kiddushin at all. Also, giving presents to one another in the yichud room, which are very expensive, is based on gemara as well.
Perhaps we can switch to lab created diamonds, which many peoole have already done; they last as long as natural ones, and have exactly the same physical, molecular properties. Only under a microscope can a jeweler with a keen eye tell by the perfect uniformity of a lab diamond that it’s not natural. They’re much cheaper than natural diamonds.
Jewelry makes a kallah feel appreciated and special to her chosson; regardless of the exact type of jewel used, it’s an important part of the formation of a zivug.
If we’re going to look to make chasunos more affordable, there are many, many things that can be done. Cheaper halls, no schmorgasboard, no 10 man band, no liqueur on every table…there are ways of making a chasuna feel just as much bakavodik, with virtually no one noticing a difference, without spending unnecessarily.