Because they are not supposed to be hitting. The only option for them as per Quran hadees and sunnah is to go for an arranged marriage. **They are not supposed to go out and start an affair. Quran orders men and women to lower their gaze while out in the public. But with so much enlightenment in the educated boys and girls how is it possible ? The educated boys and girls refuse to marry someone they do not know. They want to interact, talk and get to know the person before they marry someone. **On the contrary we find so many ahadees emphasizing to marry a women for her youth and beauty. There are some ahadees which tell you to look for the morals of the person you wish to marry. How would you decide on the beauty or morals of someone if you do not get to know the person ?
P.S.:I did not quote Quran and those ahadees because it is not a scholarly discussion about those verses and ahadees. If you are interested to know which ones go open the books please.
Ahadith do tell you to see the person before marriage and in some conditions like in a family gathering or in a public place you can talk to the person you're going to get married, also you can interact through the phone or through e-mail etc.