Transatlantic baggage allowance?

Question

Why are you able to check roughly twice as much baggage on transatlantic flights compared with flights to asia or australia?

i.e. 2x23kg bags for economy

Answer 1

Ask the airline,  

It really is no advantage if one heads home to Oz and the baggage allowance is less.  You would have to ship any excess baggage or give it up.

Answer 2

It's the same weight limit domestically and internationally on most american carriers (55 lbs which is around 23kg).  I've flown domestically in the US, from the US to Europe, and the from the US to Asia and there was NO difference in the weight limits or number of bags I was allowed.

Your question doesn't make sense.