Yes, it is happening. Ecma Office Open XML Document Format appears to win approval as an ISO/IEC Standard. And ISO and IEC have approved Office Open XML document format standard.  Open XML offers great opportunities in the areas of file and data management, data recovery, interoperability with line-of-business systems, and the long-term preservation of documents. The separation of Open XML markup, schemas, and data makes it possible to report information from various applications and systems without translating the information first.

Why IT decision makers care about Open XML? Here are media briefings and a technical discussion on Microsoft Office 2007 Open XML File Formats.