A top of the line headphone system and speaker systems are two very different things. I have both. Click on my UserID to see them. I would say both of my systems are capable of similar sound quality and detail. I listen to my speaker system 99+% of the time. When I want a fire in the fireplace and look out the windows I listen to my headphone system.
In general, headphone systems are for a contingency...when I can’t make noise, don’t have the space, traveling, can’t afford a high quality speaker system, or the environment is to noisy. There are probably a couple people out there that like them better, but there is probably some hidden reason.
Headphone systems don’t project the images and sound in front of you like a real concert, the sound stage is in between your ears. No mater how good they are there is something physically touching you.. it gets fatiguing.
On the other hand you can put together a top notch system for a tenth the cost... that is about the ratio of cost of mine. The sound with my Focal Utopia or Sennheiser 800 is simply amazing.