[cperciva]

You're pretty much preaching to the choir here; but the position I hear most often is that when we're selecting the students we want to have as part of the university community, we should pick students who will contribute something to said community (beyond "mere" academics).

In some cases, I see students' extracurricular activities as demonstrating an ability to dedicate themselves to a cause or pursuit; that sort of perseverance is important in higher education. But in most cases that sort of dedication goes along with extraordinary success of the sorts you mention. (My personal scholarship assessment rubric actually includes a specific value for "competed in the Olympics or equivalent level of international competition".)