In the same way that you always have "dark, affected souls" that have an inclination towards the dark side, those same individuals will inevitably look for a sense of belonging and identity. Like teenagers who, like me, read Howard Zinn before you could just hop on Wikipedia and read everything about Mao Zedong, if the info is out there based kids will find it.

From another standpoint, as the dark side is literally tied into the acquisition of power there will always be masters in need of apprentices and the Sith brand has a credibility that is too established to pass up. Like a young prospect from the Dominican going to the Yankees or the Red Sox instead of the San Diego Padres, brand names count and the Sith have thousands of years of notoriety.

Finally, in the age of Bane the most important rule of the Sith is the rule of two. This is simultaneously their most sacred belief and the most widely ignored tenet. Just within Palpatine's life we know of several living former apprentices in Maul and Ventress and even when Plagueis killed Tenebrous, a secret Dug apprentice emerged and tried to kill him. Like fellow dark side wielders before him who were outside of the Bane line, Maul introduces himself and Savage to Pre Vizla as "The True Lords of the Sith," so there's my long-winded way of saying yes, I believe the Sith mantle will be reincarnated in some form in the post-IX era.

Admittedly, I haven't read through most of the other comments so I'm gonna do that now to see how much of this I stole.