Not sure why this is downvoted, there are def some issues here. I find the same, there are many things like GraphQL but even SQL libraries or entire frameworks that are not easy to performance-test, or perhaps they are easy to performance test but hard to resolve.

I also agree that most of the devs I have ever worked with, in the UK, have little to no idea about how to actually test performance effectively.

Even though I am personally really interested in performance, even using a cool tool like Resharper profiler takes some time to get your head round.