They might be hard to find if you haven’t seen them already and don’t know what to search for, but there have been a number of discussions about why they are as they are and what other ways they might be. Certain forum members have argued with great passion for downgearing.
E.g.:
Not an owner of one myself but my Occam’s Razor answer would be that the Schlumpf hub is what it is because that’s what Florian himself wanted when he designed it. It was a labor of love, not an answer to consumer demands.