I have 2 years of experience calling elk so have a lot to learn and this is just my experience.
My first year I just got a call and could make a decent mew sound and that was it. I spotted a bull at daylight on day 3, closed the distance and he would answer my mews and eventually snuck in on me to about 40 yards. Ended up being a legal raghorn but never got a shot.
I decided to learn how to call and fully subscribe to Elknuts methodology. He believes that the reason people are unsuccessful calling elk is that they don't respond to the situation accordingly. Elk make sounds for a reason and they are actually saying something. If you know what they are saying, you can respond with a sound that they are looking for and call them in.
I practiced all summer and was able to call in 8 elk on opening morning. Two were bulls and my friend killed one of them. Second morning I called in bull that had cows with him (he left his cows) for a shot. Fourth day, got the herd bull bugling at 3pm in the afternoon and missed my opportunity to get him in...should have screamed over the top of him. Fifth day, called in a rag-ish 5x5.
All of this happened the first week of the CO season and I was hunting public land OTC.
Might have just been a fluke but I was comfortable with what the elk were saying and I was giving them what they wanted.
So right now, I believe calling works!
I might change my mind after this coming season!