I never used OpenDoc, but I find the idea behind it interesting:
The core idea of OpenDoc is to create small, reusable components, responsible for a specific task, such as text editing, bitmap editing, or browsing an FTP server. OpenDoc provides a framework in which these components can run together, and a document format for storing the data created by each component. These documents can then be opened on other machines, where the OpenDoc frameworks substitute suitable components for each part, even if they are from different vendors.
Instead of recreating the same set of features within each app — forcing the user to learn different ways of doing the same thing —, the idea was to abstract the core functionality of each software to make it available across the OS.
I think iOS gets closer to that but it’s probably the internet, more than anything else, that which helped unbundling the data from the underlying software — turning the latter into a service.