Your analogy relates a situation of linear complexity. You can’t even come up with an exponential growth situation to make your point?
But even if you had done so, I doubt it would be relevant. A mechanic to switch characters without relogging shouldn’t need more time than that needed to log in from scratch does now. Unless you want to claim switching characters is an inherently harder problem than logging in to the server from scratch? (please remember character selection is part of this login process…)
Basically, switching characters given 30k people is an inherently easier problem than logging in to the same server from scratch, in terms of computational complexity.
But again, this does not mean that the change would be easy to make given the game’s code architecture. I am not, and have not made that claim. It’s obviously not worth it if it requires thousands of man hours and will likely introduce many unforeseen bugs due to major changes to the game’s architecture.