Water exerts pressure in a single direction too: down. There is no PSI gradient in the lateral direction. This is intuitive because there is no force acting in that direction. I do not believe water molecules ever find a topological equilibrium in a liquid phase. Because then they would be a solid or a crystal. Water as a liquid can flow but it still only exerts pressure in the downward direction. To my analogy, pennies can slide or move from one stack to another (e.g. waves). The only thing affecting the pressure on the bottom penny of a given stack at a given instant is the number of pennies in that same stack resting on top of it. What is going on in the adjacent stacks does not matter, because gravity only pulls down.