If China became fully Christian (>50%, >70%, >90%) its Christianity, its churches, its preachers, its Christian literature, its "Christian ghetto novels, films, paintings" and such, its giving, its mission force, would eclipse Christianity elsewhere - purely because of the size of its population. (Really, even 30% Christian would likely do it.) China's overseas workers could be transformed into a mission force that would eclipse the Philippines and Korea (think tentmakers).
If India became fully Christian, the same thing. Except that India has a massive tech industry and film industry, and its global impact might be even greater.
We think, "That will never happen."
Why? Possibly because we think the odds are long against it. Possibly because we don't really want to be eclipsed.
Shouldn't our nation be the greatest Christian nation on Earth? (be it America or the UK or some place in Africa or Russia or the Vatican or whatever)
And because, for whatever reason, we think "that will never happen" - we do not work to make it happen.
But following Christ means giving up ourselves, lifting others up.