Comparitively speaking. Archers are to Melee weapons as Artillery are to Rifles.
(The ranges just scale down as the game goes on).
Technically your archer could get a shot from a hex away at my Infantry... but really who is going to win that war?
If you are still toting around archers vs. Infantry it doesn't really matter what range the archers are.
Suppose you have this arrangement:
M L L L L M
M M M M M M
m m m m m m
Where M=macemen, L=Longbowmen an m=musketmen.
The longbowmen have an unfair advantage because of the Range issue. The Musketmen will have to face this field of fire while trying to defeat the Macemen in hand-to-hand combat.
Personally, I already thought the Musketman was one of the most unfairly weak units in Civ4, relative to other units that were likely to appear during the transitions leading up to and immediately after Gunpowder. In historic battlefields the musket advantage over archers was decisive most of time, in part because of the psychological impact of gunpowder.