Exactly, and the answer is sometimes counter-intuitive. For example, I fly CX between BOS/JFK/ORD and HKG from time to time. So, BOS/JFK to HKG frequently goes NNE from takeoff up to near the Arctic Circle, then more or less due east to northern China, then almost due south through China to HKG. But ORD to HKG sometimes travels eastbound and sometimes westbound, IME it's about 50/50. It all depends.

Similarly on the return, HKG-ORD can cross the Pacific by going up over Alaska, but also can go almost due east across the mid-Pacific. HKG to JFK/BOS typically takes a more northern route, but I've approached BOS, for example, both heading south from Canada through northern NH/VT and from the west, having crossed into the U.S. near SEA.