You get 12 girls and most ~8 want to pitch.
4 of them will never put any work other than the few times you practice with them at your team practice and drop by the way side as picthers pretty quickly.
Of the 4 who do practice, 2 will decide that it is too much work to really get good and eventually drop it.
So out the 12 girls on the team an 8 that "wanted" to pitch you'll usually be lucky to find 2 who can eventually do it reasonably well.
Then they leave the rec league for travel ball. Such is life.