Standards, Business and Growth.
Strange as it may seem, once upon a time IBM sold scales and other useful things a retailer might want to have. Over the years the focus of the company changed to adopt new technologies, including large computers. A problem soon arose in that each version of the hardware used it's own unique software and nothing was really reusable. This affected not only IBM but all the other players in that market. IBM then took a punt... they decided to standardise and generalise the systems and offer a range that to all intents and purposes would be interchangeable.