Instead of fleeing to Elsewhere, Autobot flees to the Deep Wyld, taking the Jadeborn, and a population of mortals and dragonblooded with him. What would the setting look like?
Whatever the storyteller wants it to look like.
Even in real life, where endless information is available and everything obeys extensively-studied laws of physics and individual people can't turn the world upside-down, what-ifs are impossible to predict confidently. In Creation, they're even more impossible.
If I was telling the story, though...
A few First Age Exalts would follow, mostly because catching Autochthon is almost impossible and they're looking for a challenge. One or two would find Autochthon, take some kind of prize from him, and return to Creation. Apart from that, Autocthonia and Creation would be mostly independent.
The Void would never become as strong as it is in canon, as access to the Wyld would let Autochthon stave off his sickness. But endless war against the fey would provide a similar stream of deadly enemies.
Over time, the Dragonblooded would shift to Autochthonian Aspects. They'd work closely in concert with Alchemicals. Nation by nation, the role of the Terrestrials would vary. In general they'd be expected to act like Alchemicals, but despite expectations some families would end up rather aristocratic.
Other Exalts would be fairly rare, but would have left notable marks on history here and there.
Over all, the Eight Nations would be more pleasant to live in. More freedom, fewer resource shortages. But they'd also be more tumultuous, with more wars and disasters. Maybe more nations, too, forming and collapsing over the centuries.