It does, but the point is that it’s unlikely a PVP server would lack sharding since Blizzard added it for a reason. If Blizzard created a PVP server with sharding (the most likely direction), the same experience of those epic 40 v 40 wPVP settings wouldn’t happen either. So the downsides that have to exist to make a PVP server function at all wouldn’t even have the upsides a PVP server is supposed to offer.
For the player who joins a PVP server because their friends are there who want to level, they very well might. Not everyone is going to stick with a game where they are cannon fodder for more than half their leveling experience.