When the project we are following no longer runs the roadmap, the community starts to become inactive. That is the most dangerous.
Not necessary. It is important that the project developers themselves are active and get in touch, otherwise the community will really turn away from the project.
It's not so scary that a project will change its path of development, it's scary if it stops fulfilling its goals and promises made to them at all, which happens too often, and is the main reason for the collapse of projects.