Don't know if you noticed but Q crumbs were at the beginning concerning the bottom of the pyramid, now they concern the top of it, Q brought us from general things, leaving time at each stage to assimilate datas, and the stage after the crumbs make us reach the superior level.

The purpose of it is that the last crumbs we will have will concern things that wouldn't be believable if they were told first, but this background knowledge we have been fed with will make it logical and firmly argumented. Looks like education.