when a dev starts a new project before finishing the current one, it can mean a few things. First, they got inspired/creative and thought up another game and decided to make it despite having not finished their current project. second, they realized on their first project they are close to making a living off this and started a second project to get their income to where they need it to be to do so. third they know what they're doing and can handle a second project and it's their natural process to start a new project mid a current project. and last, they have no idea what they're doing and are doomed to fail.