I wouldn't worry too much about it. IME, the more you get into this, the more you realize that price
does not necessarily equal good/better, sound. Learning your preferences, how to distinguish honest reviews from hype and ignorance, and how to correlate personal experiences to measurements are most important. And diminishing returns is
very real. Once you've spent ~$150 on headphones, you are already most of the way there in terms of quality (though you may not be able to find your preference in a certain price range unfortunately). Though being audiophiles, we do want to extract those last several percentages anyway. Also, DACs and amps are not even half as important as transducers. I wouldn't say they're even 1/4 as important.
I'd take "$1000" headphones out of an iPod over "$300" headphones out of a $2000 DAC and a $3000 amp any day of the week. Though I haven't heard any ~$1000+ headphones. It's possible that there really is another big quality jump somewhere, but I'm not so sure about that. It could also be that I'm somewhat of a semi-failed audiophile or something. I don't analyze sound for pleasure, I listen to music
Sorry for the random little rant. This is just my humble experience of course.