[wesnerm2]

Microsoft did develop an HTML office format in Office 2000 for Word, Excel, and Powerpoint designed to be a replacement for the binary formats. It included extensive embedded XML. Users and companies still used the original. With Word html, people wanted all the Office specific code stripped out. Internet explorer was necessary if you wanted accurate rendering.

I was a developer in the Excel group in 2000.

[yuhong]

The same now outdated HTML export is still is in Office today and mostly unchanged since Office 2003.

[bluecat22]

So there is no technical limitation of HTML itself compared to XML (doc format)? That HTML would be a just as good replacement for XML (.doc format) if someone tried to make a word processor for it?

[wesnerm2]

The HTML document alternative was a massive technical hack. It was flawed mandate from executives in order to maintain relevance in web-based world. Embedded XML and custom styles were used to implemented the format. Also, the IE team worked closely with Office to support richer text formatting. HTML was not enough. Even then, the format still could not support all the features in the product--features like versioning, simultaneous editing, ole embedding, programmability, etc.