Well, right now, with women being trained to be bitches by feminism from the day they were born, many women are not fun to be around, even when engaged with them in sexual congress.

And so, if it is just to get your rocks off, a sex doll is quite a step up from nag-nag-nag.

Further, men have had the idea beaten into them, from the day that they were born, that they are supposed to please women in bed. And because men really do want to be good at what they do, they accept this programming easily. And so, we get too many men who are spending more energy trying to perform, and not enjoying the sex. A sexbot does not complain about you cumming to soon.

All that said, there are energy connections between men and women that bots will never be able to replicate. Along with this there is love and connection. There are many men who do not find prostitutes appealing, because they do not want sex, they want love. (or at least a women pretending to care)