So, Scepti, two thoughts, since you agree Molecules 'resist' downward pushes, in other words, push upwards, that means that at some point, the amount of pressure put down by air can't withstand the upward pressure air exerts, that must mean the force of the net push must change at some point in the atmostphere.
Additionally, if no molecules can exist in a perfect vacuum, at all, whatsoever, then how can the earth be inside it? We are nothing if not molecules, as is the supposed Ice Dome
Oh, if you sink a Submarine just underneath the surface, flood it, and then pump all the water out, it won't flatten out, as the water pressure isn't sufficient to properly compress the metal of the sub.