No one is saying it's impossible. I just think it's important to be realistic. Only 19 defencemen hit 40 points last year.
So to expect Schultz to be top-20 in d-men scoring in his rookie season is pretty lofty expectations. I do think he'll get low-to-mid-30's, though, assuming a full 82 game season, which would put him top 30-40 in d-men scoring.