When I ship a complete bike from Belgium to the US, I pay about €95 ($123). A frame only is about €62 ($82). I ship with bPost (the Belgian Post) but sometimes it gets delivered by DHL at the other end.
When packing one has to pay attention to the size, with large bikes (60cm and up) this can be a problem. Also, cardboard and other packing material comes out quite heavy, recently I packed a sub 3kg frame + form that came out close to 10kg packed!
Packing properly also takes time, effort and material, so $140 shipping is far from outrageous IMO.