I don't think I agree with the premise of this argument. BV provides an approximation of what constitutes the strength of a force, but it says nothing about how to balance a scenario. It is completely reasonable to give an attacking force a 2:1 force advantage over an entrenched defender. That decision is part of how a scenario is written. The point system you choose is simply a tool designed to help you reach that goal.
The existence of a point system does not dictate that points must always be equal on both sides.
If you want to give the more experienced player a handicap, go ahead and do it. There are no balance police waiting to kick down your door for it.
I didnt say that a points system necessitates equal points. You took that first paragraph a little out of context, and I said in my following line that there is scope to modify a scenario BV level to favor one side or another. Im not saying that BV is there to make all games balanced, but it
will balance games, without a reason not to. Without some form of narrative structure - that scenario you mentioned - as the very reason to create unbalanced BVs, most players on average will seek to fight on equal terms, because it is fair. Or, at least as fair as you can get in a rules system not designed to account for intangibles.
Narrative, scenario, and campaigns are generally the drivers behind imbalanced BVs because they give a reason, that everyone can subscribe to, for that imbalance. Without that you are asking one player to fight an uphill battle without a reason. I havent met many players over the years who will voluntarily fight a random pickup battle with 50% less points than you, for no reason. Maybe your experience is different.
EDIT: For grammar