In year 2005 CE, an Orthodox Rabbi in Florida held a wedding with mixed seating.
The results of this wedding: 3 Orthodox Jewish men met 3 Orthodox Jewish women, and they married them, and had children from them, and sent their children to yeshivahs.
If that wedding did not have mixed seating, then the 3 Orthodox Jewish men would not have met the 3 Orthodox Jewish women, who became their wives.
What I just described used to be the standard practice of most Orthodox Jews, including prominent Rabbis. Then weddings with mixed seating became unpopular, and nobody can understand how this contributes to the problems of Orthodox Jewish singles.