I am with the majority too, I´m afraid, it´s all about background for me. I even got into BTech after reading the two first Stakpole books and finding an Ad for the boardgame on the last page of one of them
The background so fascinated me, I ordered the game without knowing anything about it aside from those two novels.
I have lots of AD&D, Traveler, Shadowrun, Renegade Legion,... Sourcebooks without ever realy playing them, I just love to read about interresting settings.
Of course, there is also stuff like Full Thrust on one of my bookshelfs, which is pretty generic (and Aurora, obviously, which I have to create the background myself too)
I think there is a middleground here. I just mentioned Full Thrust. It has sort of a background, but it is very brief and realy just for flavor. A gamesystem without _any_ background will be a hard sell to most people, I belive.
Also, the gamesystem in Full Thrust is rather simple which helps one, to concentrate on creating the background for a campaign. If the rules are very complex, I have to do enough to get them streight, at least in the beginning, so I appretiate it, not to have do both at the same time (yes, I am primarily a single player guy nowadays)
Edit: I could swear your post wasn´t there when I started typing, Erik, because what you are describing is exactely the Full Thrust approach.