i have gone back through all the books and games and i tried to find an answer to this statement.
"Your forefathers wisely set aside their compassion......steeled themselves for what needed to be done.
I see now why they left you behind. You were weak - and gods must be strong"
Vigil is gonna kill me for this,but the forerunners aren't dead. i truly believe that they fled to a shield world or found some way to survive in some form.i truly don't believe they killed there entire race over the war,im nearly positive they survived.
and i think they didn't take the humans to wherever they went because we weren't ready. as much as they admired us,and wanted to protect us. they believed the best choice was to leave us on earth and hope we could defeat the flood while they couldn't.
which we did. the flood are safely locked up on the remaining rings, and the humans and elites would be very cautious when entering any found forerunner site.
I think they left us behind to follow the precursors,and that one day we will sacrifice ourselves to protect the Galaxy and follow in there steps.
Mendicant Bias also tips this cup. he says"And so here at the end of my life, I do once again betray a former
master. The path ahead is fraught with peril. But I will do all I can
to keep it stable - keep you safe. I'm not so foolish to think this
will absolve me of my sins. One life hardly balances billions. But I
would have my masters know that I have changed. And you shall be my
example. "
where else would he send john than to his masters? sure he could keep him safe be keeping him from earth. but i belive there is a higher meaning than that.