Well said! I've often thought about this as well as I auditioned various speaker rigs
None of them are perfect, but a good set of headphones like the Stax O2 does come very close (as far as headphone limitations go). Headphones will never be able to recreate the illusion of a full force uncompressed drum kit like huge horns in a big room, but those speakers will fail miserably in many other areas.
But with large speakers comes the requirement for a large listening room otherwise I've heard a few systems where the speakers overwhelm the room.
The quest for striving for near perfection is more exciting to me with a speaker rig as there are so many more variables, vs just source, amp, headphones.