Maher payment is a woman's Islamic right, it has nothing to do with wedding costs. I don't even agree with lavish weddings and think it's best to save that money for the couple's future life.
Secondly, most people are walking around with material assets worth thousands of dollars, especially these people who always have the latest iphone. But they want to act stingy when it comes to a woman who is going to risk her life to bear children?
I think both of you have the same argument.
Yes, everyone should ideally save for their future and avoid unnecessary purchases. However, lavish weddings and big mehr is a massive financial commitment.
Don't get married until you put a deposit down for a house imo.