Why do I need to be employed in order to have a girlfriend but not to have a best friend? Almost seems like the whole romantic relationship thing is transactional after all.

I am surprised you dont know the answer or maybe you are just begging. Either way I will answer sincerely. The reason is because having a partner is much more taxing on your life than a friend is. Usually people want to live with their partner and sleep in the same bed and build a life together. They usually also eventually want to start a family. You cant do that if you dont have the means of living. If you dont want a serious relationship like that then it likely doesnt matter as much but as you already know women find being poor unattractive unless you are a thug or criminal that has excitement to offer in place of resources. If you are hot enough I doubt it matters at all for a one night stand.