It looks like you're new here. If you want to get involved, click one of these buttons!
PVE MMO and servers are vastly more popular than PVP ones are.
If an open world PVP game is truly PVP, it means that 50% of the playerbase will get the short end of the stick, since they will statistically lose more fights than they will win them. At least part of this playerbase will end up leaving the game, which results in new players now becoming part of that 50% loser pool, which results in even more people leaving. Griefing probably just accelerates this process.
The way PVP works is flawed from the start, it divides the playerbase into losers and winners, which means it can never sustain itself.