I wholeheartedly agree with you. Having owned 2 kilobuck iems (Unique Melody Mirage and FAudio Dark Sky), I can definitely tell that the gap between kilobuck iems and midrange, may be around $500 or even around $300 iems are not very large. I sold Mirage, but I absolutely love Dark Sky. There are iems that sound a bit more airy than Dark Sky, bit more spacious, like MEAOES Eagle (well it sounds more spacious than any other iems in my collection)...so it does not excel above all of my collection regarding soundstage.
However, what it presents are bigger notes, which feel more real, more three-dimensionally defined, more alive! Yeah, it makes the complete music sounds so much more alive and real than all the rest of my iem, that I cannot help but appreciate and acknowledge its value as very much justified. And except Eagle, it sounds much more spacious than any other iem of mine. The whole presentation is just so big and alive...I can't even listen to anything once I start listening to it!
But does that mean my LOAK-T(CL), or Dark Matter, or Miroak-S are significantly behind it? Certainly not. The differences are at most 20%-30%, at best 40%, but definitely nowhere beyond that. And that is the reason why I have decided that I will most definitely not get any iem beyond $1500 max. That is my limit. I know hybrid, tribrid, etc. of that range will definitely sound more spacious and bigger than full range DD iems of the same range, however, I am so intoxicated by the single DD coherency that such magnificent separation, imaging, and stage have started to sound unnatural to me, incoherent sort of, and I absolutely do not want to feel such dissatisfaction with an iem of that price were I to get it.
My current wishlist iems are - Technics EAH-TZ700, Acoustune HS1750CU, Softears Twilight, and by the suggestion of a certain gentleman here, the Radius HP-W300. It is not possible for me to audition any of them, since in India they are not available, so I will have to blind buy one of them...which one - that is my current quest.