Actually that's part of why Inioch didn't relinquish the throne, according to "The Covenant" that the Archons and Elves shared, Inioch was supposed to only reign a short time, much shorter than 1000 years. He was supposed to be migrating the elves to Evermore.
Part of Inioch's justification was that he needed at least 1000 years to rule. (Though near the end it was clear he didn't intend to relinquish the throne even then. The humans jumped the gun (because of Meandor, who believed his father was going to claim that Meandor was unfit to rule, and claim that Inioch would need to raise Julia to be the next queen, thus allowing him more time on the throne.).
At least that's what was kinda going around in my head, I never fully workshopped it, so this is a great exercise...
The humans were actually "unleashed upon the world" right on schedule.
To put a kind of scifish/speculative bent on it all, just to know what I was thinking... I always thought of the Archons as having a symbiotic relationship with the Elves. Both are immortals. Archons move through the universe/planes/dimensions, whatever, finding and forming potential worlds, providing order out of chaos where they can, but they lack the role of nurturer that you need to make a cool world, beautiful and diverse. They can open rifts in space/time... etc... (this was what the new "Star" in AoW1 was all about, a rift for the fallen/slain Elves through which they returned... as you may recall from the campaign if you played the Highmen.)
The Elves, on the other hand, foster life, breath beauty and harmony. They are essentially "terraformers". From a single tear they can weave a lush forest. But they lack the power and cosmic presence to move/find new worlds.
Finally, The Humans are the Archon's offspring. Humans of exceedingly great virtue may pass on to becoming archons. Archons don't "reproduce" like we do... they enshrine the immortal souls of men with immortality, if they are disposed to exceedingly great virtue and righteousness.
In order for Humans to mature, however, they MUST be able to freely choose good over evil. If they are constrained to good or evil, then a soul does not grow as it should. Hence the need that Inioch leave, but Inioch, alas, became a devil, seeking to constrain the souls of men to the virtuous ways of Elves... and well... that boat don't float... as all of us humans know...
--Ray