You’re comparing Elixir to Python and Rails. Many of us have seen Python replaced with other languages for an astronomical improvement. Python and Ruby are the slowest category of languages; they’re easily beaten and you need to offer some evidence as to why the improvement was derived from migrating to Elixir specifically rather than moving away from Python/Rails.
I'm not dismissive of Elixir, I'm dismissive that Elixir magically solved this problem in a way other languages couldn't. If you have some supporting evidence or rationale as to why Elixir is uniquely able to solve this problem, I'm happy to hear it, but so far you've offered up "low latency GC" which isn't unique to Elixir and itself doesn't adequately explain the degree of improvement over Python (GC latency alone doesn't reduce from 200 servers to 4). Again, I'm happy to entertain arguments about why Elixir is uniquely able to improve performance, but I'm not going to take it on faith (which you interpret as 'dismissive of Elixir').
Okay, how about "a runtime that has been extremely carefully crafted for the lowest possible latency all the way to the point of the hardware falling over"?
It's very hard to provide evidence unless we make a screen-share call where I show you real time dashboards of services being bombarded with thousands of requests per second and for you to see for yourself how the median latency numbers climb from 25ms to 45ms and then fall back to 20-30ms after the burst load subsides.
I find it difficult to just describe this because as much as I've seen it many times in practice, it's also practically impossible (NDAs and compliance nightmares) to demonstrate it to a programmer outside the companies I've worked with without violating all sorts of laws. :(
But yes, basically: a super latency optimized runtime, a GC that's not very sophisticated but it elegantly dodges most GC problems by simply releasing all memory linked to an actor as soon as it quits (and Erlang/Elixir encourage you to spawn many of those in the right conditions; not for every single thing though), and one of the very fastest dynamic languages in the world, probably second only to JS's V8.
All of that is combined with me working with several other programming languages and their hosting solutions which were tripping over themselves when 1000 req/s started coming in (looking at you, Ruby 3.X and Puma and a few other servers; or PHP, or Python).
TL;DR: reliability is much better, latency is predictable.
Weirdest thing is: people don't believe it. If you only knew the CTOs I worked with: they were extremely data-driven and they would not allow me or anyone to just pull all of that out of their bottom. All had to be proven with numbers, and me and my teams did that, many times.
I understand the skepticism somewhat, but you and a few others seem to look at Elixir through the lenses of "too good to be true", and IMO you should try relaxing that skepticism to some extent. And try to be little more sympathetic because again, I literally cannot give you the hard cold data without violating at least three laws.
