Why have a standardized definition of what a "fast" website is, when Google can just impose and publish its own standards for Search, or even implement its own

Why have a standardized definition of what a "fast" website is, when Google can just impose and publish its own standards for Search, or even implement its own nontransparent standards in the back end if its worried about metrics becoming targets? I don't mean that as a sarcastic question, I don't see any problem at all with a private approach. This isn't really what people like me meant when we said we wanted Google to use performance metrics in their ranking. We wanted Google to come up with its own internal metrics, not standardize them across the entire web. Because performance isn't standard, it's extremely context-specific, and it's important that sites like search engines and browsers be able to iterate quickly on their metrics and to change them depending on what the ecosystem currently looks like. I genuinely just don't understand what value standardization has here other than to make the system easier to game and less flexible in the future. What positive, consumer-friendly, non-scammy things are possible for us to do with a universally standardized set of performance criteria that we couldn't do with privately maintained, non-standardized sets of criteria?