This argument will hold true, if Avatar acted as a normal film of 2009.
If it had $7.5 ATP in USA and grossed $540mn in USA. The growth in global market, sans China has come from inflation but in majority countries Avatar is yet to reach the current inflation, case in study most of Europe, Korea, Japan, etc.
Yes, the only thing that is in benefit of Avatar is growth in China. It is idiocy if someone thinks that Avatar will do 3x of FF8 like Avatar did of 2012. This is not how things work.
But this benefit is cancelled out with exchange rate and 3D counter point.
To sum it all, Avatar has roughly 75% of Endgame admissions worldwide, and movie going is on decline in majority of nation, including US.