The U.S. is not a monolith–registered Democrats in West Virginia have very different priorities from those in Massachusetts–so geographical boundaries actually

The U.S. is not a monolith–registered Democrats in West Virginia have very different priorities from those in Massachusetts–so geographical boundaries actually serve a purpose in electing a representative who is (ideally) aware of local needs and committed to fighting for them. In contrast, those with a common birthday or name have no distinguishable political desires in aggregate, so the likely result would be 538 generic congress members. Furthermore, if we assume people exhibit a bias toward candidates from their home state (they do, on average), grouping by birthday or last name is actually a net negative choice since it would likely result in overrepresenation of Californians in congress (assuming first-past-the-post).