most men have no control over their bodily functions to do this properly.
This is worth discussing. Perhaps I'm unique but I know when I am about to ejaculate and I could withdraw if I wanted to do that. Since I'm using condoms, I usually don't withdraw as there isn't much of a point to do so.
There are also times where I penetrate so much but don't ever get close to that near ejaculation point and then am finished off orally.
I think more men can do withdrawal properly than you think can but I also think you're correct that a good portion of men can't do this.
In all of this, we're also not talking about women's choices. Women make a conscious decision to either use some birth control method or not use one. Over time, more of the women I've had sex with were using some birth control method. It is likely also true that the women I have sex with are not a representative sample of women and their birth control choices.
Withdrawal is less necessary if the woman uses birth control. That said, I believe in Iron Rule of Tomassi #5 (Never allow a woman to be in control of the birthing) and I don't think it is a good idea for men in general to do that.