Good point, total sales is perhaps not the best measure as each generation of
airframe introduces new technology and basic fixes, as lessons are learned in the field.
Having said that the Cobra has not seen the widespread adoption, compared to other aircraft types, the totals sales for the AH 64 are in excess of 2000 airframes with 16 airforces deploying them and the AH1 Cobra has knocked up 1200 sales with 10 airforces. That is not to say it is not a good aircraft, the latest verisons of both aircraft are the bees knees and the plus point for the Cobra is that it is less than half price but not half as capable.... one could argue the Cabral is just a capable if not more so. It's the usual issue of comparing Apples with Apples.