it'll get shut down eventually. Mainly because the new one will get new features and the users will flock to new features over being super bored with old ones. And once the old site loses most of its users to the new site, the old one will shut down
Valid point, though a lot of people will still not leave because they don't want to start their collection all over again unless they can be transferred, which Brint already said no to that. So for the die hards it will be basically when they just leave altogether.