I look at their division of finances like this: These couples are right now, at the very most, dating. Yeah yeah yeah - real marriages, piece of paper, blah blah blah. But this is a trial run. There's no way I'd want to co-mingle finances with someone I was dating - or worse, someone who had either friend-zoned me or whom I had friend-zoned. So in my opinion, co-mingling finances is premature at this point in all of these relationships because what they really have are getting-to-know-you relationships regardless of how they are labeled. In that case, regardless of who makes what, 50-50 split of household bills makes the most sense. I wouldn't, for example, expect a roommate to pay more of the rent/utilities because she made more money than me. And these people are roommates right now. Maybe some are roommates who bang, but they're still roommates.
My husband and I each paid our own bills and managed our own money plus split the household expenses 50-50 when we moved in together. We didn't start sharing finances until we got married and bought a house. My husband makes a lot more than me. Like about 4x what I make. We don't keep score really. Once we made the agreement to merge our finances, we merged them. He actually told me several times I could stop working if I wanted, and I couldn't bring myself to do it. My solution to the work-mom-life balance was to be a work-at-home mom. I'm very lucky I've been able to do that, and it's kept me sane. I will say we both work full-time, our kids are grown now (in college), and the division of labor in the house still is about 80-20 (I'm the 80). Would I like him to do more? Sure. But it isn't worth it to me to keep score either financially or about division of labor because I feel that tit for tat stuff harms the relationship. Likewise, he's not really on my case about the fact I make less money than him. I make enough and I work full-time. We figure in the end it all sort of comes out in the wash and we're contributing in the best way we can.
My previous husband and I kept our own finances...paid our own bills, maintained separate accounts, credit accounts, etc., and split our living expenses 50-50. We did that even after we were married until I got pregnant with our son and I realized what a mess his finances were. Then I co-mingled them so I could pay down his bills so we could afford to have the baby and pay for his education, etc. Even after giving birth to our son, I was the primary breadwinner and I did 90 percent of everything with the kiddo, with the house, etc.
I couldn't begin to judge someone else's financial arrangements in a marriage because there are just too many factors contributing to how it all works out.