That is true to a certain extent but it's difficult to quantify the amount of cows and calves taken. In my area, the herd which wintered in my field and the field adjacent to it amounted to about 200 to 250, thirty years ago. Today, there are about 35 to 50; varying from year to year. I know that all of this population reduction is not due to legal cow calf harvest. I also know it is not due to predation. My conclusion is that it is due to range degradation, illegal harvest, and exclusion from food sources; this in combination with an over-harvest of calves and cows. I had one biologist tell me they were aiming to reduce elk herds by 20%. I told her, "congratulations. You've reduce them TO 20%". She conceded they might have overdone it. I will never see them come back.
Range degradation is a big deal. Overgrazing, along with the introduction of invasive weed species, has really hurt the available grazing for elk. Invasive weeds are spread by cattle, ATV's and logging operations. In many areas, the problem is insurmountable.
In the back country areas, motorized vehicle access has to be one of the biggest factors. The typical modern hunter is a guy, dressed camo, with Polaris tattooed on his ass, driving all over in his side x side. GD