Just because the boy and the girl are better off not having to deal with the financial negotiations doesn’t mean they’re not ready for marriage.
The same thing can be said for other aspects of shidduchim; for example, the investivations, and decision of who to go out with (although certainly the singles should have the opportunity to have input.
The Chiluk is that the investigations and decisions happen when the child is not yet married. Saying “Harei At” and accepting that ring make you (in my opinion, but I know I’m old-fashioned) instantaneously responsible for all aspects your new family, including financials. Someone who gets married had better be prepared at that point for it. Otherwise, you may have a new “friend with benefits”, but you are still a child with a child’s responsibilities.
The courts (who will require child support & alimony if she gets pregnant that night) do consider the husband responsible financially as well, as would Chazal (who are Mechayiv the Kesubah).
We will have to agree to disagree.