I don't know what it is either.
In my case, I did end up finding a very good spouse (she was worth the wait). But I didn't find her at a trad chapel!
Nevertheless, I'm not thereby going to let all the trad ladies at my trad chapels off the hook. I started off by "trying" to date the handful of young single ladies at my chapel, before I gave up and started dating pagans. In retrospect, I shouldn't have bothered. But I felt quite justified, telling my mother and other Catholics that "I tried to date traditional Catholics, but I can't be single my whole life!" It was hard. I know that many young men are in the same boat today.
For some reason, it almost seems like the young men and women at the (always small) trad chapels consider themselves brothers/sisters, or "too close of a friend to see you that way". I guess they want the modern world's version of love, excitement and infatuation over a solid Traditional Catholic foundation.
I don't think young couples realize just how important it is to be united on matters of faith and morality. Everything else falls into place.
The independent Trad chapel I grew up at only had ONE couple marry each other. The chapel was open from 1975 - 2009 or so. At its peak, it had 120 parishioners, including a lot of families and young people.
I know where most of those young people ended up. Many married non-Catholics (with or without a conversion involved), some met their spouse via the SSPX or Indult, and a few left the Faith. And a number of them never married.
I will say this: I knew one young man who was interested in a young lady from the independent chapel, but years later I found out that during his teen years (when I knew him) he was sowing his wild oats. Now I know why he didn't date any Catholics from our chapel.