I believe they will survive in some form. They will change, but every cable channel out there has evolved over time.
How long since MTV has been MUSIC television? Why does every channel have to have a reality show or 20? Why is Travel showing food shows? Why is Food showing travel shows? etc, etc.
There seems to be a strong movement in the cable industry for every channel to appeal to the broadest possible audience, and VOOM will eventually follow suit and start showing some lame reality show that follows the stupid antics of some personality that nobody really cares about. In HD of course.