It would seem that after you've got it ready to go, the skill is all gone, since you're just changing the dials based on distance, and then putting the crosshairs on the target.
As others have alluded to, it's not quite that easy. When you shoot past 500 yards things start to get dicier. Past 700 on up to 1k they really get interesting. It's certainly not as easy as changing the dials based on distance and putting the crosshairs on the target. As others have said, hold of the rifle, trigger manipulation, breath control, and many other factors count.
Not just that, though. You have to calculate your adjustments based on wind speed. Oh, and don't forget that when you're shooting 800 yards the wind could be blowing at different speeds (and even different directions) along the bullet's path. This has to be accounted for. If you don't feel much wind, but you see tree limbs swaying hard around your target you have to adjust differently than normal. Oh, and also don't forget that the angle of fire plays a pretty huge role at this distance. If you're shooting at an upward angle, you have to adjust elevation significantly more. Temperature also plays a role as well. The first shot out of a cold bore on a cool/cold day will shoot lower than normal. How much lower? Well, it's up to you to know your rifle/ammo combo. It's not just cold days that trip you up though. With the summer heat you have mirage effect, and that can really make a smallish target dance when it's 1000 yards away. Oh, and my favorite part. Judging distance. If you really want a challenge, shot unknown distance targets past 600 yards. At 600 yards, my load drops around 80 inches (yes, that's over 6 feet) from my 100 yard zero. At 700 yards, it drops around 120 inches (yes, 10 feet). So... is that target 650 yards away or 700? It makes about a 2 foot drop difference. Lets go to 900 yards. It drops around 250 inches (over 21 feet). At 1000 yards it drops around 350 inches, or nearly 30 feet. So, is your target 970 yards away or 1000 yards? The difference can mean a drop of 2 feet or so. Certainly shooting with a scope under 300 yards isn't all that challenging, even for a novice who educates himself. Shooting unknown distance targets past 600 yards is not for the novice though... especially if you do it the old school way and take away that laser range finder. Hope you're good with a mil reticle.
And then there's the fact that a consistent, day in and day out, 1 moa rifle (which is the military standard for a sniper rifle) still will only hold a 10" group at 1k yards IF you accurately estimate the distance, accurately estimate the wind speed, determine what effect the temperature/cold bore will have an adjust accordingly, make every calculation perfect, hold the rifle the same way you did when it was zero'd, do not flinch, and do not shoot as your heart beats (this absolutely matters when taking a shot like this, at least it does for me... maybe I have high blood pressure). Yes, you do everything right and a 10" group is the best you can hope for. Of course, some rifles are capable of better accuracy. It still depends on the shooter to play his part.
I once heard an associate talk about his experience when he went to blackwater's training ground in Northeastern NC (Blackwater has changed names, don't know what they are now and don't really care). I wouldn't say that the guy was known for fish tales, but he's been caught stretching the truth a little here and there. He described how everything there was amazing, and how he saw a guy there that could hit an egg at 1400 yards every time he pulled the trigger. I didn't explain my background to him (let's just say I've been there, done that, bought the T-shirt, then sold the T-shirt at a yard sale), but I know that what he described isn't possible... not first round hits every time. Heck, not even 25% of the time. A 2" egg at that distance means you have to have a rifle that will shoot .15 moa consistently, and then your math has to be perfect every time. It's certainly not as easy as "set your scope and pull the trigger."
. So very much comes into play.