Seriously, where did you find anything to suggest almost ANY of that?
It does depend a little on what you mean by “spear” - “at range” would be javelins, not spears, and “if anything got past”-type spears were for LONG spears used in formation (really SILLY long, in some cases).
The standard spear is a melee weapon that is superior to most other weapons in a great many situations. The primary weapon of the Spartans, for instance, was a spear, and they ANNIHILATED their foes with it (not just in formation usage, either), and there are literally hundreds of variations on the “spear” concept (bladed/pointy bits on a stick), used all over the world as primary weapons for literally millennia. Heck, even the lance is nothing but a slightly specialized spear.
Most bladed weapons (“swords” that today we would call long knives, and even more standard swords small enough to wear as a secondary weapon) were backup weapons, comparable to the pistol in comparison to the battle rifle - the only thing they do better is “be small enough to carry as a backup”.
The spear only faded as a primary weapon (at least for melee) with the advent of serious armor.
Personally, in a real zombie apocalypse of nearly any kind, the best way to deal with ridiculous numbers of zombies is to get a polearm of almost any kind (heck, even longer-handled garden implements would work) and get up on the roof of a nice, sturdy house. You could kill literally hundreds that way, basically at your leisure.
Shoot, a good sturdy pipe or pole, a solid lump of nearly any kind (rock or metal) and some means of attachment would even get the job done.
