Why do you think women are not going to Combat Arms MOS's?

Because not many are interested in it. Females make up less than 15% of the Army in the first place. Female enlisted accessions on average are around 13.5% annually of the total number of accessions. It was anticipated that there would be an initial surge of female officer branch transfers, but apparently even that is lower than expected. The real telling factor will be female enlisted accessions into combat arms, and the IET attrition rate.

I think that there are quite a few women on the sidelines waiting to see how this goes.
Lots of people want to be "first", even second or third. The line to be the 117th person to do something is much shorter. Pioneers are celebrated, regular joes are not.
No one wants to be the only female in a unit, always having to prove herself and reprove herself.

It is hard to say where this will really go at this point. There is a chance it dies of apathy. There is a chance that it becomes more "normal" and each infantry platoon will have a couple of females in it. I think that the highest echelons are becoming concerned that the former becomes the case.

I think the shortage of women signing up to transfer is due to different reasons that have little to do with whether it was worth opening up the MOS. First, most officers/NCOs are likely in the MOS they joined the Army to do. IOW they are in fields they likely chose, are interested in, and have been successful in. Since infantry wasn't a choice for women, it is most probable that the women in the Army now aren't women who always wanted to be infantry but had to settle foe something else. They are far more likely that they wanted to work in a combat support or service support branch to start with and have no interest in being infantry anyway. So those will not desire to transfer.

Next, you probably have some who may have been interested in combat arms had they been offered early, but aren't now. They have already been trained and gained experience and success as an officer or been promoted to NCO. They would correctly assess that to transfer would in many ways be starting over, which meanq they would instantly be behind their peers in their new field. Plus, they would know that a large number of more senior officers and NCOs in the field have been openly hostile to their presence in the MOS, making it very likely they could suffer in evaluations and hurt their careers. Trailblazers often face that obstacle.

Then you have a few that are willing to absorb all those disadvantages to give it a try, and they have signed up.

But the real future of this change lies with those women who grow up seeing the combat arms as an option, desire it and train for it in high school or college, and sign up for it. As those soldiers and officers work their way up the ranks, they will become the leaders and mentors for even more.

So IMO no one should have thought that there was a large resevoir of women already in the Army wanting to give up what they have already earned to go combat arms.but that is not reflective of whether their are women out there who will come forward in the future.

I do not think it matters if they choose not to go into Combat Arms. I think what does matter is they have that choice.

Imagine that. The females who wanted this policy change by and large never had any interest in wearing a uniform or doing the job to start with. This was never about anything more than ideologues building political capital.