Hey folks. I work at Google and closely with PageSpeed Insights and related teams, a few comments and clarifications on the discussion above..
Google Search recently published information on the upcoming page experience signals and lays out what metrics site owners should focus on. In particular, I want to call out two aspects: Core Web Vitals, and real user experience measurement. The former consists of Largest Contentful Paint (LCP; measures loading performance), First Input Delay (FID; measure responsiveness), and Cumulative Layout Shift (CLS; measures visual stability). The latter speaks to assessing performance of the page based on how real world users experienced it.
PageSpeed Insights provides a score, which is derived based on a synthetic test and should be read as a high-level signal of how well the page aligns with recommended best practices. It also provides CrUX data which reflects how real-world Chrome users experienced the page and site — the Search page experience signal is based on this. This is an important distinction to keep in mind: synthetic tests have many baked in assumptions and limitations, which means that the score from an individual run is not a guarantee of performance out in the wild. You need to monitor both, see related documentation here.
Amazon is a good example to consider: the PSI score may not be as high as you might expect, but real-world experience observed by users is actually really good and far above most other sites. Which is to say, Amazon is definitely not ignoring performance, it’s just that the assumptions in the synthetic test executed by PSI may not align well with Amazon(.com’s) user population. Also, I can say with high confidence, because I’ve worked with teams across many of these largest ecommerce sites: they care a huge deal about regions of the world with slower connection speeds, data caps, etc., and you should as well if you have customers in those regions — speed is only more important and sensitive issue for users in the regions.
Here’s a snapshot of quick benchmark report, which illustrates the point:
You can generate your own, with custom list of sites, if you install the Core Web Vitals app… or use PageSpeed Insights!