I would guess how you thought you were presenting things wasn't quite how it came across. I know that happened to me a lot. Or maybe, they just decided you weren't going anywhere and when you did, the new person says exactly the same thing and they decided maybe you were right. Why do we bring in clinicians when we know exactly what they are going to say? Because when the kids hear it from someone else it's like it's real....
Look back on your proposals and the data. Did you over analyze it? Were you being successful without it therefore they decided you didn't need it? Enjoy retirement but most importantly be happy that you made a difference for hundreds of children.