I would really like that Snail a bit curious I am now.
The top 1500 in fighter rank of tour 148 and their respective K/D. You see that there is a gradually increase in average K/D, but the individual ratings are quite irregular.
Here are the smallest and the highest K/D's appearing in different segments. Note how someone with an amazing K/D of 32 didn't even made it into the top 40:
Players that are flying very 'cautious' to get boost their K/D will often not have the result they may be hoping for. I'm a perfect example for that myself, I usually have an exceptional K/D, but my less than agressive style prevented me from ever getting fighter rank#1.
As a side note, all that is only valid for the late war arena. There are so few players and so little activity in EW in particular, that one or two sorties can get you to the top there.