I believe optics have improved, but that is certainly secondary for me. If we are talking about binoculars which you look through all day long optics are important. Just about any of today's scopes, less some cheapo 'Mart brands, are bright enough for any US hunting.
What is important is the "ruggedness" for a lack of better terms. So many people seem more interested that scope A seems slightly more clear than scope B.
They are just a place to store crosshairs. I want to be damn sure when I pull the trigger that the bullet is going where I look.