Change is upon us, whether we like it or not. HTML is the default technology for accessible documents online according to the W3C and most government standards.
That means goodbye to the easy solution of flinging scores of long documents on to a web site as Word or PDF files.
It's crazy to think we could all go back and reformat every old archived document as HTML. That's just not going to happen. But in the future, we will be forced to think harder about how to deal with the long documents we produce.
Most long documents in other formats (e.g. Word, PDF) are best converted to a collection of web pages, sometimes on a mini-web site.