(btw the comparison to mechantanim would be if each time a boy and girl date, prior to date #1 the two sides would sit down and discuss financial arrangement should the couple get engaged.”
I cannot speak for other people, but my close friend married off her eldest son, a serious and extremely bright fulltime learner, and believe you me, she was VERY upfront with the shadchan that the ONLY girls to be redt to her son were those whose families wanted a fulltime learner for their daughter and wanted to pay for full support of the couple.
If anyone wanted to be redt to him, but were not willing (or able) to do so, they did not accept the shidduch, because full financial support was what they were looking for, and he had several offers waiting in the wings who WERE willing to do so. I will not address the pros or cons of such a requirement in a shidduch, because my own personal views differ greatly, and I believe a chosson should support his kallah, even while he is in Yeshivah. I recognize that other people have a differing, valid opinion.
The point is, you don’t wait until the couple is dating for the parents to express their needs regarding something so crucial. If you are upfront with a shadchan about the things that are fiscally important to youOR to the shadchan, you avoid misunderstandings. If I can tell a shadchan my daughter will never go out with a guy who smokes (even a “little”), then that shadchan knows that that really nice, perfect Marlboro Man will not be buying her an engagement ring in this lifetime, so don’t waste his OR her time by trying to redt the shidduch.