Thomas Shey
Legend
Well, RuneQuest also has Strike Ranks, doesn't it? Which means longer weapons getting to hit first is baked into the core of the combat system? Whereas that's the rule in D&D only in 1E, and only in the single round when combatants close to melee.
That, and honestly, OD&D spears were inferior weapons which RQ ones (especially longspears) really weren't. Combine that with the fact a larger number of characters could use one effectively (pretty much all tribal types got trained in them) you just could easily end up being a simultaneously more practical and effective choice.
I mean, let's say you were wandering around with a six character party and a couple of henchmen. The latter were going to primarily be human mules, because among OD&D groups it wasn't even often assumed they'd level, nor be treated as FM for traits, so putting them on the line wasn't attractive if you wanted to keep them around for their hauling duties. By a bit in, that'd probably be two Fighters, two MU, a Cleric and a Thief. With either 2 or 3 abreast lines, who was going to be doing that second row of spears?