you are forgetting something, when you hit something, sorry for my not exceptional english, when you hit something hard say with a stick. When you hit, either you move the object as the energy is transferred. If not, the energy you get through the handle - increases.
th point isnt about penetrating anything ...
when you have a long stick in one hand, and do a forward movement with it, hit something, most of the energy transferred is from your hands holding the stick firm, so you get to absorb the recoil through your muscles. If youre weak, or the object is too resistant, then, there isnt much point to it.
If youre pretty strong that youre able to effectively wield a spear in one hand, it adds to the spears effect. When bracing, with both hands, or even against the ground vs say cavalry, the cavalry gets its own momentum used against it.
Couching, bracing helps add effective mass behind an attack. For example, a 90 kilo guy running at you with a 1,5-2m long stick, say 4 cm diameter, and you standing there, receiving the stick when said guy has it braced, not lounging, just ramming. Instead of the whole body impacting, the braced stick will transfer the energy from the 90 kilo guy running with minimal loss compared to it being held by 1 hand, or being thrust forward. I would not want to be on the receiving end of the stick.
Putting a long spewar/pike against ground, against things like horses to prevent the horse from falling on you and to not have to absorb the horse charging, but the ground doing it.
So again, a 90 kilo guy bracing a longer stick, running, or you being 90 kg running against a braced stick at a correct angle, what would happen ? Somebody woul be knocked out on the ground or on the way to hospital.