This is inaccurate. I have started looking again into solutions only last week [1]. My suspicion was always the database pool size was too small but, when I tried to contribute 4+ years ago, fine tuning was hard because it took too long, so I didn't pursue it further [2].
My discontent with the benchmarks is that they are not measuring what people effectively run in production. Since you mentioned Rails, here is how a Rails application looks like:
https://github.com/TechEmpower/FrameworkBenchmarks/blob/mast...
But almost nobody runs a Rails application like that in production.
And then you look at the configuration of most stacks and they have been explicitly fine tuned to match exactly the concurrency traffic and patterns that the benchmark sends through. But, for most web applications, your web traffic is not homogeneous and you don't have a predetermined number of concurrent requests.
I still believe those benchmarks are not indicative of what you will actually see in production. Most companies who have gone from Rails to Phoenix, for example, report a 10-20x reduction in operation size and costs. But it is clear at this point people put way too much stock on these benchmarks. The irony of it all is that, if someone copies these setups into their actual applications, they will most likely perform worse. Oh well.
[1]: https://github.com/TechEmpower/FrameworkBenchmarks/pull/9302
[2]: https://github.com/TechEmpower/FrameworkBenchmarks/pull/5432 - here you can see me increasing the database pool to 40... but most benchmarks today run with 512-1024 connections (which, once again, is most likely not what you would do in prod). In any case, we need to bump our numbers accordingly.