Getting back to the OP’s post about reducing the cost of getting married by eliminating the engagement ring.
Over a number of generations and many decades of observation it is my observation that the woman’s family bears the brunt of the cost of the marriage. The chassun and or his family having to buy an engagement ring has little effect on the cost of getting married.
My parents generation paid for their daughters’ weddings, I and my brothers paid for our daughters’ weddings. My sins have paid for the weddings of granddaughters who have reached that age. Yes, the boys’ side may have made a small contribution towards the total by paying for license, Ketubah, personal flowers and occasionally liquor or music; but the vast majority of the expense falls on the kallah’s family. I discussed this after minyan this morning. Of the 12 present, there have been 5 children or grandchildren married in the past 3 months in Brooklyn, Monsey and Lakewood. In each case the kallah’s family paid for more than 75% of the costs.
The cost of an engagement ring not purchased would not reduce the expense to the kallah’s family, it might just lower total money spent, not up the contribution by the other side