bit off topic, but IF your return/onward flight(s) is/are operated by a different airline (and since you also seem to have open jaw involved), your chances might be bit better. i once had a ticket RGNxKULxNRT/---/LAXxJFKxHELoBKKoKULxRGN. I missed first three flights (operated by MH and JL), but was still able to board AA flight from LAX to JFK few months later and also use both AY longhauls (JFK-HEL and HEL-BKK). Last two segments (op by MH) were cancelled however from the day I missed my outbound segments and MH was not eager to reinstate them back. So YMMV.