Sure - and when jQuery was first released it was super-tiny too. The reality is that: 1) Targeting a single platform will yield a smaller file size at the expense of market share. 2) Shooting for small file size will throw important features and functionality under the bus.

I mean - either it's feature complete and it's small or it's not feature complete and its size is unknown. A large portion of the linked-to site is dedicated to the size of the library so I assumed that it was feature complete (as did most of the people in this thread).