KDEnLive is a KDE application and most people here use GNOME. However, all
of the *buntus share the same repositories so some will be running it
anyway. Not everybody sticks with the default applications (Ubuntu ships
with PiTiVi).

The sound is configured in the settings because many people who edit videos
have multiple sound and video cards. Your setup may be simple but some
people use Myth TV and have a graphics card for the computer, a TV card or
two and more graphics cards. Some of those will have built in sound cards
and others will need more than one sound card to work with the various
graphics cards.

However, his issue is, "why doesn't it remember the setting."

He's not alone in this, although I've never observed it myself.

My settings save and work. I use the application all of the time without a
problem. My setup is normal. His situation is very unusual and I am not sure
that I fully understand the way that he has it setup. I think that he is
asking the impossible and have tried to suggest alternative solutions that
might be more fruitful. We seem to be going in circles.