: Halo is primarily set 500 years in our future
: where humanity exists in the same light as we do today to great degree,
: and like ourselves, we've barely come close to eschewing all that
: separates 2014 from 500 years in our past.

and hey don't forget, 2004 is canon :) ilovebees.com exists in Halo's (and our) past!

: Halo has immense potential to be a culturally influential franchise as long
: as the stories that drive it stay relevant and force us to ask questions
: merely than something to sit back and consume.

Yep. It seems to be the people that want it to "end" and of the ilk who believe Halo is just a single story, or just a video game series; in their case, dropping more words out the window is "milking", stretching it past its intended point.
But no, the universe is rich with hints of people, places, and events that haven't yet been explored. Significant aspects of the timeline that each had a place.

I hesitate to say, Halo Wars sort of demonstrated that. There was an accepted history and timeline regarding humanity and the flood, and then Halo Wars was released which told a story that was completely disconnected from the history and content we knew, leaving a door open with a mystery, yet still not connecting in any way. Some saw it as a needless story that had no effect on things, so was a desperate attempt to release something new in the franchise that could exist independently created by a '3rd party' (non-Bungie) developer. But now we're seeing how that story is tying into the grander narrative.
Who cares whether its connection was written in later or if it was planned all along. I don't. as long as it's good and it works and it fuels my love for the Halo universe :)