The problem with standards is that there are so many of them. How this leaning tower of Babel came to be, and how you can best cope with it is the topic of this series of articles. Unfortunately, things have changed a bit since then. To make numbers bigger than 1 you have to add more bits. With seven bits you can have exactly 128 different possible combinations of 0's and 1's.
Keyboards are another.
And, once again, historical accident and American industrial predominance are at the heart of the matter. The keys on a computer keyboard are really just buttons that, when pressed, send electrical signals to the computer. Change the mapping and the same keycode will map to an entirely different character code. This is really a very clever scheme, providing a great deal of flexibility. By simply changing the keyboard mapping table you can get a different keyboard layout without having to build a brand-new keyboard.