Because the ability is here since day 1, all units with it are being used on regular basis and it was never an issue until some 4 digit 4v4 RT hero lost to it, because moving rocket arty after barrage is extreme micro to him.
"Because the ability is here since day 1"
????
you just proved my point, its an extremely outdated ability. Almost every single unit since then has gained major changes in abilities because they just simply dont fit the game anymore. abilities that are free and require zero user input should be in this category.