I think that the Steiner thing about 7 was that this is the time most children are losing their baby teeth and getting their adult teeth. They see this as also a significant transition from the magical, dreamlike state of early childhood to a much more reality-based, grounded middle childhood. (But I'm no expert on Steiner so corrections are welcome

).
I definitely have noticed my dd seeming so much more grown-up over the last year (she has just turned 8). She still likes believing in fairies and Santa, but also asks many more questions. I can see her struggle of wanting to hold on to the magic, but also needing to move forward to understanding more about what is real and what is imaginary.
My ds will be 7 in October. He still loves living in the world of his imagination. His favourite thing on mornings we don't have to get up is hopping into my bed and making my hand become a character who he talks to. Even when his sister tells him "It's not real you know, it's just mum talking and moving her hand" he says, "I know that, but it IS real".
I just love this stage, and I know I will miss it when he grows beyond this stage too. It's such a special time.
J