It is happening again..,
Thing is
@Brewpub even if the BGS was open only, it's a simple numbers game as to who has the most influence. Therefore a bigger, well organised group will win vs a small group merely because they interact with the BGS more. As others have also pointed out, you have PS4 and XBOX players also contributing, not to mention different timezones. The other base assumption you are making is on instancing. Even in Open, I could very well instance in a different er... instance to where you are waiting to blow me to smithereens or at least counter my activity.
Your assumptions at the base level are wrong I am sorry to say and therefore an "Open Only" BGS won't happen. Honestly, let it go.
If by some miracle it was available - killing non-NPC "enemy" ships has very little effect in the grand scheme of the BGS, this is why there are so many NPC ships to murder if you see fit. Top BGS manipulation is never about the pew-pew.
Now, should there be a Open Only feature that IS dependent on PvP (in whatever form, not just pew) then from me the answer is YES!
Powerplay SHOULD and COULD have been this, but it's a decision that was mooted by FDEV and then quietly allowed to die. I tell you, people lost their minds on the boards here when it was suggested.
Us Open Only Powerplay advocates still live in hope, but for the BGS to go Open Only please refer to the video below.
Source: https://youtu.be/L0MK7qz13bU