you are missing the point. No coach would ever accept blatant one on one missed tackle (well Kearney
does with Thompson).One missed tackle in a one on one has far more effect than a player who may miss four but each time it is in a big collision and the tackle is completed by someone else.
Trent Robinson ,a premiership winning coach, is on record as saying Maloney misses a lot of tackles but makes the key ones (when he was the roosters)
Missed tackles alone is a crude stat to use to gauge defensive ability. It can point to a problem but it only really makes sense once you' analyse the tackles to see what happened