While a Phalangite formation is very good at the defensive I doubt that in a frontal fight they can push the Hoplites back. And as Dutchhoplite posted, the power of an crowd shouldn't be underestimated, the pure pushing power would, in an prolonged melee be enough to break the Phalangites. I think that the spears of the Phalangites wouldn't be able to take that much presure, unless the formation slowly walks backwards. Might be what happened at Chaoronea with the Thebans staying where they stood because they were the more disciplined troops, or with Phillip actually risking his left by having them stay put and his right slowly walk backward.