Sounds like another grind vs grind system to me..
The whole point about PvP & BGS warfare is a defending faction should be able to provide a deterrent to the attacking group via opposition, rebuys and eventually stop them in their tracks altogether.
Also many people talk about instancing/platforms/blocking etc as a reason it wouldn't work, but this is just agenda-driven whataboutery in my opinion. If the risk of direct opposition exists, BGS groups would have to go about their gameplay far differently - the game would be better for it.
No other serious multiplayer game out there would let players directly influence the world and other player groups from the total safety of a private mode... It's terrible game design IMO.
EDIT: As for the OPs point, no it's not a myth... it just depends what group you're attacking. Groups like mine (The Code) and Privateers Alliance will defend their systems in open. However we're all aware of how pointless this is because of the design flaws, so have to resort to other less interesting gameplay to see off the solo warriors.
BGS groups would be quite happy, I think, to go about their game in a different way, but the game would probably not be any better for it at all.
Off the top of my head - if I was one of those ultra-competitive players who was always looking for a way to get the upper hand - I'd be going about the game differently - like you suggest, above - but, I must warn you that you are not going to like this because it illustrates why your entire point is meaningless.
So, yes, I'd be going about my game far differently - and I'd be doing these things:
1. Play on at least 2 different platforms
IN OPEN - in order to leverage the best advantage and not encounter the opposition.
2. Figure out the quiet time and active time of the opposition group - and deliberately go online
IN OPEN during the quiet time (on the least active platform for that group)
I'm no internet whizz, but if I was an ultra-competitive type (you know - the type of player that comprise the majority of PvP groups...) then I might also consider:
3. Experiment with throttling my internet connection speed and other network settings - in order that matchmaking has a low chance of instancing me with players with fast connections (you know - the "committed gamer" type of player with a fast machine, etc... who, in a Venn diagram, has a large overlap with the PvP type player?)
So, yes, I *would* be going about my game in a totally different way, gut I cam assure you 100% that the game would not be better for it.
Fortunately for me, I'm not an ultra-competitive PvP type player, and it therefore appears to me that I get far more enjoyment out of this game than those that are ultra-competitive PvP types, because of the way the game was designed, with forethought and intent, from the ground up, as a peer-to-peer game.
I genuinely feel sorry for those that think this game should have been designed a different way - to better suit *their* enjoyment - although that last point does limit my empathy somewhat, because, so far as I can tell, it is always "all about me" (and not, as you say, "for the good of the game").
Yours Aye
Mark H