I appreciate the desire for specific data to back up theories. I really don't know if there is really a strategy to inflate the number of congregations. I have not seen enough proof. But a post from Germany not long ago piqued my interest. It was an analysis of the number of German language congregations compared to foreign. The numbers seemed to indicate the drop in German congregations was masked by formation of foreign congregations. I'm not good with the search function, so I can't pull it up.
My observation involves only two kingdom halls. Both are in the western US, in separate states. I can confirm that each of these small congregations are full fledged congregations with their own bodies of elders, separate from the English congregations. But that is only 2 congregations out of 119,000 worldwide.
My opinion is that most people in foreign language and ASL are honestly deluded and sincerely want to help disadvantaged foreigners in their communities. If there are ulterior motives, it could be to make busy work for the more zealous drones, and to massage the egos of some who enjoy bragging rights of working where the need is greater. Each additional congregation opens up positions of perceived power, at least on the Service Committee. Three more elders, three more Elderettes.