PW is still technically open, so the reason that nobody plays is strictly that nobody plays - not because admins or faction leaders fail, but because of inherent design flaws.
For majority of the public, PW is just unbalanced teamgames, and for the competitive PW players, PW is mostly uncoordinated noobfest that draws the worst from both worlds: unbalanced as a meta-4x game and just as riddled with mixed-skill as regular teams 20x20zkdsd clusterfuck.
Restart has been proposed earlier, but there is no point of restarting it without adressing the issues that caused the current round to stagnate in the first place - even despite Dynasty's best efforts to instigate the raging of war on an unprecedented scale.