Either Debian is the Rock of Gibraltar or it is not. I think we can consider Debian to be reasonably permanent. Ubuntu, standing on the shoulders of Debian might be considered permanent in the way that, say, the Hawaiian islands are permanent. Sure, they might fall below the waves someday. But no one worries about visiting there or moving there. My analogy fails at the point that it does fall below the waves. Because Ubuntu has revitalized the concept basing distros upon Debian. Debian, due to Ubuntu, has regained its position as a substantial force in the Linux world. If Ubuntu were to fail, a new Debian-based distro would take its place. I am probably making myself look like a Debian fanboy. And I am not. I rather dislike Debian. I'm a Red Hat/CentOS/Fedora guy! But I like what Ubuntu has done with it. And now the world has seen what can be done with Debian. That genie cannot easily be put back into the bottle.