Our alphabet is derived from the Roman which is derived from Greek which is derived from Phoenician. Our uppercase letters are copied from Roman versions meant

Our alphabet is derived from the Roman which is derived from Greek which is derived from Phoenician. Our uppercase letters are copied from Roman versions meant to be carved on stone. The lowercase are derived from medieval variants (mainly Carolingian) designed to be written by hand. So lowercase letters were designed with speed in mind. Though, interestingly, if you write uppercase fast (like I and a lot of other people do) you tend to reproduce the evolution of lowercase.