The international territories where Dunkirk is most relevant are the mature ones where studios actually make good ancillary cash. The UK, Australia, Germany, France, etc. It would be cool to see a $75M+ gross in China to boost the ww gross, but in the long run the difference between that and $30M in China isn't really a big deal.
Every dollar of UK box office ends up being worth more than $4 of Chinese box office over the lifespan of the film.
Great point.