Few points of contention. Not sure how many will read all of this since it's quite long.
1. THX is also a certification that needs to be paid for. Many A/V Receivers are capable of producing the same quality audio as THX certified A/V Receivers, they just didn't pay for the logo.
2. Hi-Res Audio and High Resolution Audio are ambiguous and confusing, and personally wish they could have a set rule. But saying it is more suitable for studio use is extremely wrong and a poor (wo)man's opinion. There are many music and audio enthusiests that can differentiate and appreciate the difference between CD, SACD, and what enthusiests consider "high res audio". Try listening to Pink Floyd's "The Wall", Dire Straits "Brothers In Arms", or Tom Petty "Wildflower" both on CD and then in High Res, with proper equipement, and then state your opinion. Even comparing High Res music to vinyl is quite different because they still use normalization techniques before recording to vinyl. That, of course, also depends on musical tastes as well as a full appreciation to music. It's one thing to analize on paper what the headphones are capable of, but it's quite different to hear it and appreciate it.
3. You need actual high res audio files, and a player (software), to appreciate the headphones to their full potential. MP3, or even FLAC is wasted on this. And I'm willing to bet there are no games that are capable of playing high res audio. And their "sound stage" is also dependent on the player as well as the headset.
4. The actual drivers in the headset are the same ones that are in the Arctis Pro and the Arctis Pro Wireless. The $70 for the high quality DAC is a good price, as you mentioned, but but now days a lot of newer cell phones are capable of playing high res audio files even higher than what the DAC is capable of, with the correct software installed. And, yes, this will play on the Arctis Pro Wireless with the analog cable that is provided. The only reason why the Arctis Pro + DAC is "certified" hi-res is because of the DAC. But all three headsets are capable of playing the same hi-res music.
Yes, these may seem on the expensive side for gaming headphones, but these are very low, entry level priced headphones when compared to a basic, decent DAC/headphone amp starting at $500, and headphones getting into the butt-hurt price range. I, myself, am an audio enthusiest and have a deep appreciation for music, as well as really enjoy gaming. I've been reading up on headphones for a long time and trying to figure out how I can afford the things I want, a gaming headset so I don't piss off the neighbours at night, and a high res audio player and headphones to match. Sadly, I'm on disability and funds are very limited. These things have been on a wish list for a long time while I kept researching. I came across the Arctis Pro + DAC and thought these were going to be absolutely perfect for what I wanted and could afford. Then I found out that I could hook the Arctis Pro + DAC to my cell phone to take them on the go, but it would literally be hooking up a DAC on top of a DAC. And, as you pointed out, with more limitations. As I pointed out, the Arcis Pro Wireless have the same drivers as the Pro + DAC, and you just have to hook them up with the cable provided. Lets me use my cell phone to play high res audio with Neutron Music Player, as well as game wirelessly on my computer. I could have opted for the cheaper Arctis Pro and used the cables provided with that, but I decided to splurge (much to my fiance's wrath).