It doesn't exist!
Well, actually it does. I guess I can't conclusively state that. But unless at least two specific women in my life have "faked it", repeatedly, over many many years, and have lied about it's existence in their own bodies, then I'm pretty sure it exists.
I think in reality, there may be other things going on. Maybe some women aren't as in tune with their bodies. Maybe some just don't get any pleasure from that spot. It might akin to female ejaculation - some women can do it and some can't.
I just hope that the result of this study leads people to believe that a) if you have a g-spot, celebrate it; and b) if you don't get any pleasure from it - focus on other things! No need to fell bad or anything.