Orvis Tertia,

A lot of this has to do with what time period one is interested in. From about 500 BC to 100 BC archery was not all that great from what I've gathered so far. I doubt very many of our campaigns get past that. Later the bows were improved and adopted by more and more successive cultures. The compound bow had been around a long time, but not every culture employed it militarily, and even when they did many were not that successful. There were exceptions: cretan archers were very effective for one. But when you consider all those Persian archers vs. the Greeks and later Alexander's Macedonians, you don't get much of an impression that archers were as powerful as we are seeing. The fact that Rome didn't seem to field "homegrown" archers during the time of the Republic is telling. Later they did field archers, but much of this came in response to the Parthian horse archers, who had an even more powerful compound bow that did well vs. armour. Carthage used lots of Balearic slingers, but few archers.

I suspect that the bow/arrow as a military weapon had not yet reached a state of development that made it more desirable than slings or javelins, except in the hands of the very skilled/or in a few cultures. It would be more challenging to get uniformly equipped and trained archers than slingers, javs, swords, or spears. Since most armies were not fully professional at the time (or at least were not put together with the intent of that), archery would be more challenging to incorporate properly. Much farther back (up to about 1200 BC) one of the deciding factors in chariot warfare was that the better equipped chariot riders also had much more expensive/difficult to make compound bows that gave them a considerable range advantage over foot archers. Since the charioteers were either elite or nobility, one gets the sense that good archery was not something accessible to the masses of the army. But anyone could use a sling and get performance equivalent/better than the primitive bows available to the masses.

Javelins and slings were not super powerful either, but the generals of the RTW time period who wrote about such things preferred the range and effectiveness of slingers over most archers they had at their disposal.

Javelins were probably nearing their zenith at this time, true. But they had also metamorphised into heavier pila employed by the infantry. And these stuck around longer with Roman armies. The javelins (with units such as peltasts) were used to "develop" the enemy position, drive in opposing skirmishers, protect vulnerable flanks of hoplites and such. They could wear down an enemy. Several of Sparta's defeats were dealt by small forces of peltasts wearing down isolated hoplites. Mounted javelins were very common. The Numidian mounted javelineers were extremely deadly even to other cavalry despite being very ligtly protected and having little for defense other than a fast horse, leather shield, and their missiles.

Like you, I also have a hard time citing major battles of the time that were decided primarily by ranged weapons except for a few like Samarkand (actually a rather small engagement, though important) and Carrhae (which is substantially later and forced a change of army composition for Rome.) The ranged weapons were usually much more of a secondary supporting role rather than pivotal. However, there are a number of small actions where Greek hoplites were taken apart by sustained skirmisher harrassment.