First I do need to give respect where it is due on the reference to PSL - not what I was expecting and fair play.I just feel like Pierre-Simon Laplace felt about God: "I have no need of that hypothesis." I don't think there's anything that it's needed to explain; it's just an ad hoc conjecture out of nowhere. And I resist the tendency to assume that every single thing that happens in the Delta Quadrant has to be about the Borg. They were overused enough in the show itself.
I mean, both your points could apply just as well to the Federation, which was reachable by transwarp and whose members and neighbors were definitely aware of the threat the Borg posed. But a ton of stuff happened in TNG and DS9 that had nothing whatsoever to do with the Borg.
Second - of course it is! The OP made comment on wondering why Voy had such a high number of "one and done" races, I put forth my theory on how it could be impacted by the Borg - precisely because of how much the Borg were used and from season 4 seemed to be a constant threat and presence.
Third - the way it is presented is such that in the Delta Quadrant they are almost unchallenged whereas every time they come up against the Federation after Q Who they get their arses handed to them so stop wasting resources on it.
Its lovely that we have differing views - that is what the board is for; but also knowing when views are entrenched or constructed on fundamentally different points of view is key and I think we are just going to go in circles if we carry on down this path
Parts of Eastern Europe have Asian influences culturally due to close contact through war, conquest and trade.