Before 1864, a bolt or screw made in one machine shop wouldn't fit a nut made in another machine shop. Everything was proprietary.

William Sellers proposed a standard that became adopted as the U.S. Standard and subsequently developed into the American Standard Coarse Series and Fine Series. So screw could be made in Chicago, and nut made in New York, and assembly could happen anywhere. Everything worked together.

Apply that same logic to IT and you arrive at Open Standards.