Meanwhile if you fatten up by 20kgs you fly for the same price. Just eat your clothes!
Even first class passengers can't turn up with unlimited luggage but, in my experience relating to families flying between London and the middle East, have household staff who make arrangements and coordinate with carriers.
When I fly between London and East Asia I shop around between different carriers and, in economy class, I'm normally offered up to two checked bags with a total weight of between 30 and 35kg depending on carrier and promotional offers.