I’ve no source for this, just personal speculation.
* There is a good case to be made that there were female deacons (ministerial servants) in the Bible.
* There is a “lack” of “qualified” brothers for basic assignments such as microphones, accounts, literature. In some cases, elders have had to do double duty because of a lack of ministerial servants or “qualified” brothers.
* Women outnumber men in the organization.
* There is supposedly a surprising change coming "down the pipe".
Perhaps the only difference between male and female ministerial servants is that women will still not be allowed to “teach”.