Exactly. There is an entire package of tools and development process which, combined, makes things work out. The fact that you need an entire package, and the difficulty of adopting multiple simultaneous changes to change how you work is one of the primary reasons that I do not recommend that organizations all rush out and adopt Google's strategy. There really is an all or nothing thing here.
As an illustration of the dragons that wait, what happens if someone adopts all of the tools and practices, but the product manager is still able to put real schedule pressure on developers. I guarantee that in the rush to finish features that anyone who holds up implementation with, "This code is crap and there is no way I'm approving it" will come under pressure to accept the crap code. And as soon as you cross that line, the entire strategy falls apart because, even though in theory you're following a good process, in practice you just lost a critical underpinning.
As an illustration of the dragons that wait, what happens if someone adopts all of the tools and practices, but the product manager is still able to put real schedule pressure on developers. I guarantee that in the rush to finish features that anyone who holds up implementation with, "This code is crap and there is no way I'm approving it" will come under pressure to accept the crap code. And as soon as you cross that line, the entire strategy falls apart because, even though in theory you're following a good process, in practice you just lost a critical underpinning.