Brisker-
I’m not sure if there will be less people in kollel, but it is likely that there will be more people working. Most seem to forget that as the years go on, the frum, yeshivish population is growing by leaps and bounds. Each kollel couple that gets married is likely to add 8-10 more jewish neshamos to the world. Out of those 8 children if four end up working and four end up learning, both the kollel scene and the work force will each grow tremendously.