Good quality optics, with a well-designed reticle, are definitely an aid to range estimation, but not the answer. The fella behind the glass is the most important part.
One of the best I've seen at ranging in a Basic class was Ninja_Moose. Crappy Bushnell 10x with a simple mil dot reticle, he correctly ranged every single target on the first go 'round. Outstanding! I've had a few other folks do that over the years, but they were all during private classes where they get more "one on one" time with the Instructor.
The purpose of fighting is to win. There is no possible victory in defense. The sword is more important than the shield and skill is more important than either. The final weapon is the brain. All else is supplemental. John Steinbeck
"A 99 percent shooter with a 1 percent brain will almost invariably be beaten in a gunfight by the 1 percent shooter who has a 99 percent brain. Since the dawn of mankind, humans have had to rely on their thinking prowess to survive. The firearm is merely the means to attain the end." Louis Awerbuck
Fear the man, not the weapon!