I had a fairly high end Stax rig before building my speaker system. The speakers image and soundstage in a way that is physically impossible for headphones to accomplish. You go from sound in between your ears to performers seemingly in the room with you. Given the resolving prowess of electrostatic headphones, this was an area I assumed the headphones would hold advantage. Suprised to say there wasn’t much in it, with the headphones perhaps displaying a bit more detail in the lowest levels. I achieve higher engagement from the speakers, as well. Presence, weight, and tactility can not be matched by headphones.
In my opinion the remaining advantages of headphones are isolation and nulling the room effect. The price argument is indeterminate. Flagship headphones are over $4000, with some headphone and amp pairings costing over $30,000. Achieving high end sound from a headphone system requires the same care and attention to detail as a speaker system, sans room treatment.