Wallace also rejected Pietsch’s qualms with the inclusion of endnotes [in Infinite Jest]. Pietsch preferred the easier to read footnotes. But Wallace said that endnotes let him 

make the primary-text an easier read while at once 1) allowing a discursive, authorial intrusive style w/o Finneganizing the story, 2) mimic the information-flood and data-triage I expect’d be an even bigger part of US life 15 years hence. 3) have a lot more technical/medical verisimilitude 4) allow/make the reader go literally physically ‘back and forth’ in a way that perhaps cutely mimics some of the story’s thematic concerns ... 5) feel emotionally like I’m satisfying your request for compression of text without sacrificing enormous amounts of stuff.

He later told Charlie Rose that 

There is a way, it seems to me, that reality is fractured right now. ... The difficulty about writing about that reality is that text is very linear, it’s very unified. I am constantly on the lookout for ways to fracture the text that aren’t totally disoriented. You can take the lines and jumble them up, and that’s nicely fractured, but nobody’s going to read it.