For the case of ' what happened ' to 2010 BattleScape; OSRS happened. The majority of people playing private servers back then was to relive the old days of PKing, when OSRS came out a lot of servers lost their player base, as for BattleScape in particular we have a reputation so to speak. Lots of resets. That usually scares the veterans from coming back. I doubt we will have that amount of player again, and we'll never 'Bring back' old servers as they do not exist anymore.
As for PKing as of now the rewards could definitely be tweaked, we heavily depend on player feedback and suggestions so if nobody suggests things they wont be changed. At the moment the current pkers have nobody else to fight unless they ask in the Home cc, or they hunt PvMers doing bosses or Revenants. We have events, but those are mostly player driven. The staff team rarely holds events with rewards that anyone would bother to join 'EI. like 200m cash for first place, 150 for second and 100 for third' its really a waste of their time for so little.
Again, we run off of player suggestions. If you have any suggestions of your own in terms of PKing (rewards etc) make sure you let us know.