My guess is you're the only one who notices. When guests look at your tank all they see are the corals and fish, telling you how cool it all is. You reluctantly agree knowing the tank is all scratched up (how could they NOT notice?). If your eyes are focused several inches into the water, you can hardly see the scratches IME. I have a used glass tank that has scratches and even blotchy looking "etchings" (from coraline?) that I didn't notice when I bought it. Thought I could clean it all up. They become magnified in water and when hit with intense lighting.
My suggestion: keep overlooking the scratches, look at the cool stuff inside.