There is a little bit of that effect in scope lenses, but it usually affects definition more than brightness.
For years Swarovski used larger interior lenses in all their 30mm scopes and claimed extra brightness, but they also used better glass in those scopes. One major side-effect, however, was a relatively narrow adjustment range. This year they finally came out with "tactical" 30mm scopes that essentially use lenses for 1" tubes, allowing for the extra adjustment so many shooters want these days, and they're just as bright as their larger-lenses 30mm scopes. They also cost around $3000.
