No logic, just a hypothesis based on assumption that most people in the pool are from the sub-continent. Also, even if people from major french speaking countries join in the pool or are in the pool at this moment with good french scores, they merely would be 10-20% of the total candidates and I am being generous here. As per the last released stats, there are 48K people in total the pool. Out of which, less than 4K are now there in the pool standing below 423.
New people will, of course, join in but the pool will be flushing out candidates in parallel, and the ratio of people getting out is greater than the ones joining in.