I think there is two main reasons for this.
Firstly, men and women are fundamentally different. If a man sees a picture of a naked woman he is ready to go, straight away, regardless of whether she has a great personality, or whether she is nice, or whether she is intelligent. Men are attracted to beauty and youth, since on an evolutionary level, these two characters are what men crave. Women, at least in my experience, mostly only want to fuck a guy they like, that ticks all the boxes, makes her laugh, makes her feel safe... Whatever. We're just different. As men, we have our heart, our dicks and our mind, and we can be attracted to a woman on either level. With women, usually all three are connected.
Secondly, most women are entitled. They get chatted up, complimented, get gifts, get dinners bought for them, get taken on holidays. Men spoil women to get sex, so women get used to this. Sex to women is a weapon. And sex is usually something that is got with difficulty. So when you can pay £150 to sleep with a gorgeous 24-year-old who will make all your fantasies come true, that weapon becomes less powerful.
In short, women control the access to sex, and it is their greatest power.