Another read on this is well... WWS started off late last-gen wanting to build their studios to be multi-project/multi-team studios. Rather than investing in buying studios, they've attempted to put more money into existing studios.
I would say that initiative hasn't exactly turned out with glowing results.
ND's co-presidents talked about how difficult it was to hire the right staff to fully staff up two teams and that their flat structure means there is a lot of collaboration and it never makes full sense to completely silo off teams.
And in terms of actual results... ND came out the gate really strong with Uncharted 3 and TLoU as the result of their two-project approach.
But it's debatable that Uncharted 3... never really realised its full potential, given that key parts of UC1/2's talent was off working on TLoU, on top of its schedule. TLoU managed to deliver, but then we see Amy Hennig's Uncharted 4 end up in a situation where they basically cancelled that project, and had Bruce/Neil step in to reboot that project.
They still managed to crank out great games, but it's hard to not see that some distillation of talent and resources ended up costing UC4 to be in a weird position where it had to be rebooted.
Killzone Shadowfall and Horizon are another two situations, where Shadowfall's quality is not seen as highly as the best that GG can deliver, and the fact that Horizon has scored this well has also implications that Steven/Eric were not as experienced to take the mantle of the IP. Steven was a new director, as well.
Suffice to say, Stig Asmussen's new IP being cancelled.... God of War Ascension being not so great are SSM's example.
Media Molecule and San Diego also hasn't been exactly successful at handling two projects.
It's been a difficult lesson for WWS in terms of stretching their development skills to working on multiple games.