> Even at Google, there will be different teams who will deviate from the "described process" given their business context, setup, or stakeholders.

Seriously. A lot of the book was influenced by Social SRE who had opinions all out of proportion to their own importance and success. At the time, there was some doubt about whether Social's pet theories belonged in the book, considering the varying practices and beliefs of other SRE groups supporting products that people actually use.

This is related to my rule that anybody can title their doc "Best Practices" even if nobody subscribes to them.