Here is a WotC interview with Richard Baker.
Richard Baker says something tantalising.
So we settled on the idea of producing an “ultimate” Dark Sun, returning to that golden moment of the original set. The events of the Prism Pentad may unfold in your new Dark Sun campaign more or less as they did in the novels, or they might not. This is a world where the exploits of Rikus, Neeva, Sadira, and the rest are only one possibility among many.
Could Athas in this view not only have variant futures, but also variant pasts? Had Richard Baker ever given thought about how a different past or future may have played out?