In the case of the TechEmpower benchmarks, i'd argue that it's actually pretty much the same thing as real world applications:
https://github.com/TechEmpower/FrameworkBenchmarksFor example, look at a full platform Java Spring Boot example here: https://github.com/TechEmpower/FrameworkBenchmarks/tree/mast...
The controller code, the model code and even the repository code are all very reflective of the primitives you'd find in production code.
The only differences would be when you add additional complexity, such as validations and other code into the mix, such as additional service calls etc., but if even the simpler stuff in Python (as an example) would be noticeably slower, then it stands to reason that it wouldn't get magically faster on the basis of less overhead alone.
The exceptions to this which i could imagine would be calls to native code, since the aforementioned Python has an amazing number crunching or machine learning support, but that is hardly relevant to web development in most cases.
Otherwise we risk running into the "No true Scotsman" fallacy: https://en.wikipedia.org/wiki/No_true_Scotsman
In such a case, we'd adamantly claim that these benchmarks are simply not good enough even for educated guesses and we'd have to build out our full system to benchmark it, which no one actually has the resources for - in practice you'd develop a system and then would have to do a big rewrite, as was the case with PHP and Facebook, as well as many other companies.
On the other hand, premature optimization and dogmatic beliefs are the opposite end of the spectrum: you don't need to write everything in Rust if using Ruby would get your small application out the door in a more reasonable amount of time.
There are no easy answers, everything depends on the context (e.g. small web dev shop vs an enterprise platform to be used by millions) and the concerns (e.g. resource usage and server budget vs being the first to market, as well as developer knowledge of tech stacks, for example market conditions of PHP vs Rust).
Regardless, in my eyes, there's definitely a lot of value in these attempts to compare idiomatic interpretations of common logic for web development primitives (serving network requests in a known set of formats).