That's because "glass" is the most overrated item in the optics spectrum when it comes to rifle scopes. Your scopes mission is not to read news papers at 500 + yds. It's to put rounds on targets. In most cases if you can see your target thru the scope glass, you can hit it, as long as your adjustments are true, you can read the wind, know your loads dope, practice at range, manage mirage, establish good trigger control and have a good rest.
Notice in most of the cases that a civvy finds themselves in, none of the above have anything to do with "glass quality".
And yes, you do get what you pay for in optics, but "glass quality" is only one of many bennies you get when spending more $ on a scope. And by far one of lessor importance, compared to build quality, service after purchase, good reticle design, and robust & repeatable adjustments, just to name a few.
Just a minor example: Athlon Helos 2-12x42mm costs less than $500. Leupold's Mark 5HD 2-10x30 with illumination cost $2500.
I've shot side by side other shooters with my little Helos and their "better" Leupold and their better "glass quality" in the Leupy meant exactly ziltch.
Now as we go up in scope power, say from 20x and up, glass quality or lack thereof really shows up in overall clarity and light transmission. Yet those very high scope powers in use are often negated by mirage, rendering them near useless often.
None of this is to say don't spend big money on rifle optics, but rather consider all elements in your proposed optics package, of which "glass quality" is just one of many elements that rounds out a rifle scope.