You seem to be under the impression that it can only be one extreme or the other. Sony's first party devs have been sharing too much over the past few years, and it's becoming more obvious as time goes by. Should their studios be at each other's throats? No. Should their studios be up each others ass so as to make many aspects of their games too similar? No. There's a massive middle ground between the two. Surely you don't either fight or screw everyone you meet do you?
What aspects of their games are too similar? What game mechanics? What story themes and plot beats? Character designs? Art design? What things can you point to and say with certainty that they are too samey? Focusing on third-person, action-adventure story/narrative-driven games isn't enough of a prerequisite.
You're vastly underestimating the costs involved with high-tier AAA game development; there's a financial reason their studios share techniques and technologies with one another and it's only been beneficial for them in doing so, not a detriment.
As for the rest? I guess we'll just have to wait and see the results, but I can't honestly say that I share your enthusiasm. None of Sony's first party studios have succeeded in any measurable way in their multiplayer games, much less a live service one which is somewhat of a further progression from just multiplayer.
Well that's what the Bungie acquisition was for; to provide experience from one of the best in the industry when it comes to live-service content.
While it wasn't your intent, you perfectly highlight the issue. You point to ND's talents in character animations, as though it suggests they're fully capable of making a decent multiplayer game. That's not even factoring in the live service aspect. Character animation has about as little to do with making a decent multiplayer game as matchmaking does with creating a singleplayer one.
Again, that's where studios like Bungie, and yet even others like Guerrilla and Insomniac come into the picture, and it's not like Naught Dog haven't already taken a go at MP content with both inclusion in the original TLOU and Uncharted 4's MP component; they aren't oblivious to what it takes to make a multiplayer component.
Making something that's a live-service? Well that's up to the air, if they are even interested in doing a game along those lines. But the reason I mentioned them as an example (among other Sony 1P studios) is because they definitely excel in the area of visual fidelity, character animations etc. beyond any other MP-centric or live-service game on the market, and a lot of that work in the single-player space can be translated to a multiplayer space (they've already shown this to be the case in the past with things like Killzone: ShadowFall's MP mode).
Combining that with proven MP/live-service game design from experienced teams like those of Bungie could result in some wild innovations in the MP-centric/live-service space when it comes to presentation, production values combined with tight gameplay, content, and shooting mechanics/physics. It'll be pretty interesting to see how this initiative develops over time.