Which first requires a definition of balance in the context of a game where PvP is an optional extra.
In practice, it wasn't an optional extra in Open prior to 2016. Player density was sufficient that most any well known mining area, trade hotspot, rares system, and certainly any CG had significant numbers of CMDRs roaming around at all hours, some of whom would have been hostile. TTKs were short enough prior to Engineering that passively waiting out the log off timer was a dubious proposition. The only people who virtually never had to account for PvP encounters in Open were dedicated explorers, or cheaters.
PvP is a side effect of each player being able to choose to shoot at anything they instance with. It's hardly intrinsic.
PvP was quite intrinsic to the early Open experience. That it flows from the ability to shoot anything one instances with doesn't diminish that. The game would have been radically different without those encounters and without the potential for those encounters, probably unrecognizable.
Frontier realised early that players don't enjoy going backwards
I feel like we've been going backwards since at least Beta 3. Actually, Beta 1 had plenty of stuff that was replaced with inferior versions later. I don't have any hands on experience with anything prior to Beta 1, but I've heard accounts of mechanisms from the Premium Betas and earlier that weren't carried into the final game (e.g. a supply chain simulation) that I'm convinced should have been.
There have been plenty of additions I've enjoyed, but for the overwhelming majority of the game's existence, I've felt like it's been on the decline.
- as they found out after the bugged NPC loadouts released with enhanced NPC challenge and Engineering in 2.1 - the engineering commodities that NPC were attacking players for were quickly removed and the NPC changes dialed back (much to the chagrin of some players).
I'm not sure what that has to with going backwards.
.... if these bits are ignored I suppose:
The first bit doesn't mention modes, the second is the 'barely touched on' part.
Given Frontier's comments around the time of the introduction of PMFs, they understood well the implications of the game modes - and chose not to side with those who prefer PvP.
Even if that were the case, if I wasn't aware of Frontier's designs to undermine the Open experience (which certainly wasn't mentioned in the game's marketing materials), how would more casual players or non-forum participants have known?
A big part of your arguments around PvP and modes has revolved around the idea that players chose the wrong game through their own willful ignorance. I've followed the game fairly closely since late 2013 (not as closely as some certainly--I didn't actually back the game until after the kickstarter and was never part of the DDF or anything--but far more closely than the overwheming majority of the player base) and I was caught largely off guard by Frontier's growing neglect and increasing hostility to Open in general. It wasn't until probably mid-2015 that I fully realized Frontier didn't care much about balance, internal consistency, or delivering what was in the development plan.