The numbers don't lie. Fast response time may not be your #1 priority, but
the 144 Hz TN gaming monitors are faster (see link). I am guessing that if BenQ or ASUS could make an IPS with that kind of speed they would, but right now they can't.
EDIT: It is also very important to point out that refresh rate and input delay are not the same thing. Even a 120 Hz monitor can have input lag and not every 60 Hz monitor has the same input lag.
Yes, just because some folks can't see a noticeable difference doesn't mean that difference isn't there. That's not to say a difference is unacceptable or bad necessarily, as it all comes down to personal needs and wants. I get the impression that most decent LCD monitors, even IPS, are more than adequate for most, even gamers.
I remember people laughing at my Dell laptop I showed up with to CS and CS:S competitions years ago when everyone was still lugging around their CRT. I still ended up dominating, and it's not magic. "Fast" gaming monitors are largely a marketing ploy, probably one level above "gaming network cards." There's perceivable differences, but for the large part it doesn't matter. What people don't understand is your brain fills in the information it needs. You can tell the difference side by side, but afterwards it will quickly adjust. It's similar how you can assemble a 3D world out of multi-monitor setup. Furthermore, since LAN's are largely a thing of the past, today's world of online play and lag further negates the minuscule differences in image timing.
What your brain can't compensate for is the awful image quality a TN panel gives. There's no point in playing a game if you're staring at garbage, even if it's refreshing slightly faster. The importance increases if you do even more things with your computer, like content creation, movies, etc. Anywho, as you can see in this thread, some people have been sold hook, line, and sinker on faster refresh while these companies are laughing all the way to the bank.
Your brain can compensate for about anything to an extent, including poor picture quality. At the very least, it adjusts and gets used to different things.
It is true that a faster monitor isn't going to make up for lesser skills. Not that skills and in-game stats are everything...have you considered that some people are just more comfortable (eye strain) playing on a faster monitor regardless of skill? I primarily use a higher refresh rate for comfort and eye strain purposes rather than for gaming, though the smoother motion absolutely helps to a small degree.
Also, have you read the articles on 2D LightBoost? I've seen a gamer's KDR for Battlefield 3 posted, and it had a noticeable increase after said gamer started using 2D LightBoost. Why? A much clearer image while in motion. Your brain can only compensate so much for "imperfect" information (ghosting, motion blur, etc.), and some are more sensitive to smooth and clear motion than others. Also, certain games will see more benefit from clearer, smoother motion than others. Battlefield 3 is obviously a good example of a game that benefits, as would CS. Some simply care more about higher refresh rates and clearer motion than perfect picture quality. That said, a gamer will likely see more benefit going to 2D LightBoost than they will going from 60Hz to 120Hz (2D LightBoost already has the benefit of requiring at least 100Hz refresh rate, though you need the rig to push those frames in games or you get judder).
You're also exaggerating the lesser picture quality of TN panels. While there are some truly terrible high refresh rate monitors on the market, you can get 120Hz displays geared towards gaming that are actually quite good in all areas except maybe viewing angles (easy to work with unless you are clueless when it comes to monitor placement or are stuck in a less-than-optimal setup). 120Hz panels have been so beneficial to my eyes even outside of gaming (less eye strain due to smoother movements...I can see differences in refresh rates up to around 100-110Hz or so). My brain can only compensate for 60Hz so much now...I can never un-see the difference if there's any sort of motion on the display. Picture quality is still very important to me, but it doesn't do much to help with eye strain. This is, of course, assuming I'm not using a terrible TN panel, but apparently the hardcore IPS users have tried nothing but terrible TNs...
This is why I have my PLS monitor OCed to 120Hz. I literally get the best of both worlds while the rest of you make exaggerated claims to "prove" your personal needs and tastes as some sort of fact. Don't get me wrong...I've steered people towards 60Hz displays if I knew they had no need for a higher refresh rate but did need solid picture quality.
Also, LAN parties aren't quite dead yet. Indiana University has 2 large ones a year, a couple of which have been around 400-500 people the past two school years.