Not really, autorouting is generally extremely bad. Especially for applications with such high performance criteria. On the plus side the work only has to be done once since later motherboards are mostly just iterations on a previous design.
For example, Xpedition's sketch routing feature: https://www.youtube.com/watch?v=fIi13gI9xEA
Routing 4094 signals sounds daunting, but it is a bit less daunting when you realize that a good fraction of them are power/ground (and route directly to planes), and the rest of them are mostly logically organized into buses/groups that can be routed together.
Seems like it's almost boring these days since everything's encapsulated in a layer of abstraction. A lot of the more complicated wiring is in breaking out PCI-e channels into things like ethernet, audio, and other miscellaneous ports that involve good chunks of analog circuitry.