And no it is not because I am trying to protect patriarchy but it simply is backwards to what you want to do with a strategy. Let me explain.
They likely will not attract enough women to the 4B movement to affect the dating market but let's assume they do. Abortion is a big part of their frustration. When I have looked at surveys about abortion about the same percentage of women are pro-life as men. In fact, sometimes women are more pro-life than men. Thus pro-life men are not going to be hurting in the dating market seeking pro-life women. If they cannot find a date or wife or sexual partner then it is because they have no game and not because of 4B.
So if there is an effect on the dating market, then it will be on pro-choice men. They are the ones who will find it harder to have a partner. Indeed, given that a lot of men will do whatever they can for sexual access, a lack of available pro-choice women will drive them toward pro-life women who will pressure them on the abortion issue. This movement provides an incentive for men to become pro-life to gain sexual and marital access. Not the outcome I think these women want.
When you develop a strategy it should punish your enemies and reward your friends. The 4b movement does the opposite of that. Regardless of how you feel about abortion, feminism or Trump, this is a poor strategy.