Seems to me that there must have been a huge counter-cultural movement in the AoL to attract 50% of AS to the DO. Then you had world leaders such as Ishamael and Graendal joining or changing dramatically during this time ... it would be like Oprah joining up!

Perhaps like the modern BA, AS of the AoL converted because they simply could not live up to the societal expectations. Only later did the more ruthless ones start upping the ante. Seems to me that during the Collapse there must have been much more personal benefit for an AS to join the DO ... not all of these people could have been like the 29 who were granted access to the TP. I suspect the vast majority of the Dark Side AS were along the lines of the rank and file AS of the modern age. Basically selfish people who didn't want to bear the burden of the entire society any longer.

Then you had the true Forsaken the men and women like Ishamael and Lanfear who were broken individuals seeking to dominate others. These were the truly depraved individuals. Certainly there were many of these people, but from Moghedien's thoughts only 29 individuals were ever allowed access to the TP so I imagine most of the lesser Forsaken were the minions of the greater.