I've been a good doobee and joined SCBWI, gone to conferences, joined critique groups, gotten an MFA in Writing for Children, read tons, written reams, edited, edited and edited. Yet all I get is rejected, rejected, rejected.You're doing all the right things. Unfortunately, one of the right things (for a bunch of people) is collecting rejections and working for years before getting published. Sorry about that.
What am I doing wrong?
This is why I hope writers are doing this work because they love writing—because there's no guarantee you'll be published (though working hard and being patient make an important difference), and if you do, there's truly no guarantee that it will ever make up for the time and effort in dollars.