Oh I’m with you. It’s true that more expensive ‘usually’ means better, and that giant killers are as rare as hen’s teeth. But there are exceptions, and notable ones too. For example it might seem strange to call the HD800 a ‘giant killer’ considering its giant reputation, but even being a decade-old design it easily slays some $3000+ headphones if that’s the sound you’re after.
Likewise the FiiO M11, at least compared to many $800+ DAPs (though that’s more of a ‘costs less but is still better’ example that a giant killer).
The FH7, for me, is a true giant killer only because it fits my sound and comfort preferences so well, that I wouldn’t buy 2-3x more expensive IEMs even if they were equally priced. Is it the last word in technicalities/capabilities compared to some $2k+ IEMs. Probably not, but I’ll bet it’s more comfortable and better built, which is 50% of the equation with universal IEMs, and I’m not one of those people who would spend hundreds or thousands of dollars for subtle sonic improvements.
I usually like to push right up to the point where diminishing returns fall off a cliff, and I think I’m just about there with all of my gear.