Earlier quoted context omitted.
I would believe this.... if 1. games made 15 or 20 years ago 2. and indie games made today would not be able to manage it. It's always the bigger studios who utterly mess up in making an actually playable game, which indicates that the problem is not something inherent but a simple product of laziness and greed. (Latest example: see Creative Assembly's meltdown)
As scope increases all the organizational challenges balloon. Coordinating 10 people is much easier than several hundred. It's the same almost regardless of domain. What happens if your core game loop still is no fun, but you got 100 people rolling off a previous project and ready for the next phase of this new project to get to where you need them to start design levels and assets? It's much easier to fix if the add…
Best case study is Mojang, the company has over 800 employees but it is literally outperformed in game design and update quality/quantity by ten people at Re-Logic. (which includes managers and legal as well!)