I am going to take a guess at answering your question---but am no expert. All the poly battings I have seen say maximum quilting distance of 2"-4" as you stated. I have never taken a commercially made comforter apart, so don't know if there is something available in that market that allows for larger spacing. But I have seen many old comforters with uneven and lumpy batting in it , which would indicate not enough quilting to prevent the batting from shifting, separating and balling up between the fabric layers. So I would be Leary of purchasing a commercially made comforter like in your first picture unless it was going to be used in a guest room and would not be washed a lot. Also I have seen lots of comforters in stores that say dry clean only----maybe that is how they get by with less quilting spacing!!