These games all got support and funding from Sony as well as Sony Engineers and tech advisors checking in and helping. So relying on them wasn't an issue. That and they have already established a set of good games in the previous gen, so it's not like Sony hired a new group with a tarnished history. For Spiderman they literally went to them, asked them what they want to make, they said Spiderman and Sony not only helped fund the project, but let them have as much time as they needed, funded them and sent additional support where it was needed.
Yes..but Insomniac WANTED to make the game. If Insomniac had said no or they were working on another big game, then Sony would of had to have gone to someone else.
Last year Mike Ybarra was playing God of War on Mixer before E3 and he was asked about Sunset Overdrive 2, and he stated that Insomniac has to want to make a Sunset Overdrive 2
Sony can't always rely on Insomniac to make games for them, or Bluepoint, or From Software. It doesn't matter how much money, time, resources and support they offer them, they have no control over Insomniac wanting to make a Sony published game or not.