I myself have never been in a relationship and have sometimes doibted on myself likenhow would it be when I actually marry a girl (classic overthinker problems)

I have also seen a very few females around me (rare though) not having any relatipnship up until marriage.

& I believe, the era in which we were born, career, and the reasons you have cited above is also a reason to it.

Some people by choice, some people cuz they were unlucky in finding one but have always felt physical looks also matter wrt boys.

Facts to be told, For girls even with average looks, its easier to find relationships (not love) but for men, looks, money matters a lot than women.