We're also very likely to get a "technology flyover" situation - in the past, if Caesar wanted to send something (even just a message) fast to the edge of the Empire, he needed a road the entire way.

If Lincoln wanted troops moved to the front, he needed rails, or lots of roads and time.

Now we can travel and communicate between vastly distant areas without intervening connections - you just need an airport in Perth and something resembling a landing strip in the Outback, and you have travel. Satellites and radio preclude the need for wires to be run.

If humans do go extinct, it's going to be from a lack of will rather than a lack of means.