With PVP there would be wins or losses. Assets and credits could be drained. Influence and Rep. This would also prompt more movement through out the BGS in places like colonia. We wouldnt have 8 month BGS wars. There would be progression past that point.
If it drained peoples assets and credits and can see people not bothering with the BGS at all. It would just become another failure of a system which nobody in their right mind would want it be a part of. Then that leads to the game failing again.
You are really not looking at the big picture at all. All you are doing is looking at what you personally want. Just because it is what you want doesn't mean it will be good or a success. So far the BGS is a success and works very well, not perfect though.
They tried that gameplay in Powerplay and it is an utter failure. That maybe because it is in all three modes, but it maybe because most people are just not interested in that kind of gameplay.
You make a lot of assumptions to back up your ideas. You shouldn't as assumptions have a habit of blowing up in your face especially if they are not thought through enough.