A small part of the puzzle may lie in the fact that some, if not many, members are or have become seasonal. That is to say they crunch only at certain times of the year. Take for example, a grammar/high school student. During the school season, students are using their computers (many or most are laptops) for studies, and later they may enjoy some after study entertainment like gaming. Not much if any crunching will get done. During the summer is when many of these students may leave their systems on and idle long enough for BOINC to kick in. After all, when was the last time you say anyone under the age of 21 dragging around a laptop? It's all about the latest smart phone and/or tablet.