Why are most cold cuts still round?
Last time I checked, most bread was square, but most cold cuts like Bologna are round, so whenever you make a sandwich, chances are your cold cuts aren't going to cover the whole slice of bread.
The solution is simple, either the bread should be round, or the cold cuts should be square and since it's much harder to make round bread, it seems to me that cold cut companies should work out a way to make square cold cuts. Thankfully, cheese and most hams come are already square, but somehow salami and bologna are still round.