I believe it is partly ArenaNet’s responsibility to get the servers somewhat balanced.
Of course they can not control people’s decisions and actions, but they can influence them, they can set up systems that lead to a more balanced playing field
Offering guilds that have a high turnout in the desired timezone a move to a server that needs more of those, complete with transfered Guild-Benefits etc might be one of that.
Adjusting the points-gain based on realm population might be another.
Have everyone creating a new character/account enter their “Core Play-Time” (e.g. evenings CET) and suggest them servers based on that.
Pair up/combine one EU and one US server to fight together against 2 other pairs.
Some of these options are way more work than other, but the point is that there -are- plenty of options other than doing nothing and expecting the players to solve the issues them-selfs.