Okay, now you imagine there being one playlist in Halo, where you can't decide whether you want to play 16-player matches or 4-person arenas, where you have a 15% chance of getting SWAT rules, a 15% chance of getting Shotty Snipers, a 15% chance of getting Grifball, a 15% chance of getting matched up for the campaign, and the remaining 40% is split evenly between BR-starts and AR-starts. Where your party might be kept intact, or split up into Doubles, or even shattered to make room for a 16-player Lone Wolves match.
We're not talking about segmenting the Souls playerbase into fifty different communities, and it's a little ridiculous that you thought that was an apt comparison.
The Souls community is segregated into four camps:
1) People who play offline because they're unable to or don't want to play online.
2) People who play offline because it's the only 100%-reliable method of avoiding PvP, even though they'd rather play online for soapstone messages and/or co-op.
3) People who play online and don't like invasions and forced-PvP (Lumping in together people who dislike it but put up with it, people who dislike it and disconnect when they get invaded, people who dislike it and cheat to make it irrelevant, people who dislike it and so use mods that prevent invasions, etc).
4) People who play online and enjoy invasions.
A hypothetical PvP Toggle-enabled version of the Souls community would be segregated into three camps:
1) People who play offline because they're unable to or don't want to play online.
2) People who play online and don't like invasions and forced-PvP.
3) People who play online and enjoy invasions.
The first group is unaffected. The second group is desegregated into the third, and both of those groups are then allowed to have an experience that is substantially more enjoyable for them. The fourth group is only affected inasmuch as they will only be able to PvP with players who share their preference. They are no longer allowed to buoy and sustain themselves by essentially acting as a parasite on the third group, but their experience is made much more "pure" because they will only invade and be invaded by people who are interested in that sort of play, meaning far fewer botched invasions where the invadee disconnects or uses cheats/lag switches to avoid the encounter, and a far greater number of proper "fair fights" where neither player is a helpless, unprepared pushover to the other.
If the PvP-on portion of the community were large enough to comprise a healthy, active userbase, then everyone playing the game is happy except for people who literally, specifically, want to force people to stop enjoying themselves and to stop having fun playing the game they want to play.
If it isn't a large enough portion of the community to comprise a healthy, active userbase, then obviously invasions are not anywhere near as "crucial" to the game's success or identity as you'd like to believe.
This is so well said. Nicely done.