[katkatkatkatket]

>Surely a new set of common experiences increases the diversity of thought of all the participants?

This statement is absurd on its face. The entire premise of the benefits of diversity (of thought and experience) is predicated on the subjects in question having had unique experiences.

>Is it your contention that a new experience deletes or diminishes previous experiences?

Somewhat, yes. When I went to university, the shared experiences there hugely overshadowed what I had experienced in my prior education.