I was too young at the time to really debate someone on what books were good and which were slop/drivel, and by the time I was old enough, it's popularity and marketing machines were already peaked. I remember crying when pottermore gave me the wrong house. Much is obvious in retrospect, but it would be nice to see what someone who was an adult at the time and saw things as they were, in historical context, could fill us in on how this incident spiraled out of control.
The best I could guess tho, it was "good enough", got some heavy luck, right-place, right-time. You couldn't repeat the success today because most YA competitors just do most things better.