First of all, you gotta calm down. Secondly, did you read my post (the second message of this thread). It explains why there cannot be 500 players in a Jet Age game world (there never has been, and never will be since it simply does not work as the pax demand levels for that era are so small.). But as I mentioned it has been a while since the last full game world and with the UI upgrades there are now more people wishing to join, so having no spaces in the new world so soon is unfortunate but expected though. But it's still not a good reason to "ruin" the game world by cramming it too full.
Also to avoid any misunderstandings - you are not paying any credits if you are not in a game world. And the Credits do not expire if you do not use them, if you login to your account at least every 6-7 months or so (no need to play even then, just log in). But I am sure you are familiar with this, just that the example you made isn't very suitable ..
Anyways; The Beginner scenario has been just launched ahead of schedule to cater for the immediate gaming needs. And as posted in the news the Dawn of the Millennium scenario is next to start with exact starting date being announced in a week or two.