Until then, all odds are stacked against them. They’re going to go extinct in an instant on a cosmic timescale. Unless, of course, humans choose to bring them along and save them from that fate.
Perhaps a scholar in 320 AD would also have been surprised by how remarkable it was that the true purpose of human intelligence had only been so recently discovered.
This is the chasm that needs to be crossed. Its not just the immediate advantage your species gets from intelligence. It’s cultivating that to a point where you realize all life on this planet is default extinct. Then getting your species to the point where you even have a _chance_ of changing that default.
Humans are still default extinct. We are on a path to changing that default.
I agree that the ultimate purpose of any species is to continue to exist. I'm just skeptical because your definition of that is so related to modern science fiction