It's a solution that would work because Crystal proved that.

But it's also problematic because many people will immediately just transfer back to Aether, Crystal or Primal.

They will feel upset at being forced to leave their FC behind which is restricted to their world/DC.

In many cases there are DC-specific communities for hunts, raids and other activities, forcing them to choose between that or their homeworld they have been on for years with their FC.

The situation is better now because we have DC travel, but traveling is just annoying because you have to logout, and SE forces you to go through the launcher and 2FA all over again if you have been logged in for only a few days. That makes traveling even more annoying, even if you can handle the hurdle of logging out and waiting at the start screen for a while and losing communication with your home DC.