Melee, on the other hand, is shut down by simply kiting them until your CDs are up and using that to turn the fight, something you cannot do as a Melee against a Ranged attacker.
Don't melee weapons have more mobility in general than ranged?
So a crossbow puts on a robe and oneshots a sword wearing a robe before the sword even gets close enough to attack
That crossbow has to stand still for a while to shoot its E, and you've got plenty of time to hit a defensive ability/potion and close the distance.
Overall, in your post it sounds like you're assuming equal starting position and numbers, which sounds like 5v5s. Aren't melee weapons useful in 5v5s?