Your conclusion is wrong. Darts cannot hold a candle to bows, if this was the case far more people would use darts, me included Darts are far less accurate than you assume and the damage isnt as high as you claim either, its all very good getting numbers from a calculator but if you actually compare darts and bows ingame the result is quite different.
Oh sweet irony! I actually just finished a gen as a long bowman, And am now using war darts as my main weapon, I find that the damage is significantly less per shot, and that they blow at range, But i get within 15 feet or so, and people get wrecked! My K/d As a bowman was about 1-1, But as a Wardarteer, I usually go 1.5-1 and I am only level 26! Yes, I get what you are saying, but at the same time, If you play to the darts strengths, and avoid the weaknesses (Long range) you can really roflstomp!