Despite popular belief, anything procedural based is essentially repetition of the same handful of things. GI, IR, pain, interventional cards, and even ENT/Uro/gen surg bread and butter. You are essentially doing the same handful of procedures week in and week out. To students shadowing or spending a day here and there it probably seems like variety because you are seeing it for the first time as a student. The docs do the same handful of procedures every single day and most of them likely go similarly unless there is a complication in which case variety isn't your friend.
Variety is going to come when you're dealing with a large undifferentiated patient population. In the hospital these will always be your EM, IM, trauma teams. The consultants (GI, cards, colorectal surg, ENT, Uro, etc) generally are consulted for the same handful of reasons and they perform the same handful of procedures. Through your career as a consultant new standards of care will come along, new procedures, new ways to do procedures, etc will come along and you'll adapt but for the most part that's then what you will do.
It really depends on your definition of variety, the size of the organ system, patient population you are interested in. In general critical care, EM, general IM, trauma surgery (ortho/gen surg), FM, high risk OBGYN will have a significantly larger decision burden than GI doing scopes all day
