This has long been a bugaboo of mine in the game. But, you smack right into the romanticism of the sword. Spears just aren't sexy. The image of shield and sword, or the samurai with his katana or Conan with his honking big sword is just far, far too ingrained into the minds of fantasy fans. The fact that a sword was almost always the weapon of last resort gets largely left by the wayside when you have to wade through a thousand years of King Arthur stories.
Never minding the inherent classism here as well. Spears are peasant weapons. Swords are a symbol of knighthood and wealth and status. Again, the romanticism of fantasy will trump any attempt to make spears considerably better than they are. Same as slings. The weapon of peasants and the conquered, they will never be considered even remotely on par with longbows.
It's just the nature of fantasy.