The blanket is very nice and the step niece is thoughtless.
I had the same experience. I made two quilts for my sister-in-law and her husband for Christmas. I even made matching pillows. They live very far away. I got a picture of their daughter-in-law, who was sick, wrapped up in one. No real thank you. They hadn't even realized that I made them until we talked at a later date. Nor had they seen that I had named the quilts and dedicated them to each one and "signed" my name.
They are not young so we can't blame the lack of manners on age!