I am increasingly convinced that Haskell only exists so that people who know it can pat themselves on the back for being wonderful.
(Btw, this, actual stuff people use, is how I measure programming languages -- this metric takes into account communities, libraries, practical issues, etc all together, and ties them with practical results. It's my version of "let the market decide").
But you're talking more about products than programming languages. Haskell contributed a LOT to programming theory.
Your every day coding is most likely using things coming directly from Haskell without you knowing it.
This is a feat in and of itself.
There are certainly applicants from the groups you mentioned, and we do our best to filter them out.
It's interesting to hire people for stacks that most programmers have no production experience with (and have pretty much no way of getting), but it's certainly been done before.
In my view the tech in a startup pretty much doesn't matter. You either make something someone will pay for, or you don't, and then you die whether you use Fortran or Coq. Thus you might as well make yourself comfortable for the ride and use whatever you'll enjoy building stuff in, something you won't be easily bored of using and teaching others.
If you get to the stage where you need to quickly bring up to speed hundreds of developers, you pretty much already made it and you're experiencing growing pains, that's a good problem to have. Most of your code won't survive that scale without a serious rewrite anyway. You'll deal with that when you get there. The vast majority of people will never get that far.
I know quite a few professional programmers who credit Haskell with making programming fun for them again (this holds true for me too and my production skill set includes php, c, c++, python, ruby, erlang, scheme, javascript, scala).
And I just don't find Haskell (or Lisp) to be as productive as many would suggest, even if you adjust for matureness of the ecosystem. (Note: I have a moderate experience with Lisp, very little experience with Haskell and these days mostly program in Java, Julia and Python.)
I despise that people give their 2 cents for something they haven't experienced much.
>I have ... very little experience with Haskell
So, how would you know?
Do you have experience using haskell? If not, you are being hypocritical. Please stop.
Yes, that's what banks are most known for. Showing off how clever they are and not doing anything useful. Facebook and google certainly fit that profile as well right?
It seems rather hard to evaluate the tail end from "little experience".
Not always true, sometimes you can have a fairly good picture of something after a short time.
Haskell to me felt exactly like what you described: I could get stuff done fast because of how few head-scratchers I'd experience. This is mostly due to type mismatches, and how much more well thought our my design needed to be upfront. I also really enjoyed the language because I could express fairly complex thoughts in a very succinct, and yet very readable fashion, mostly thanks to types being explicit and enforced at compile time. Code reuse and sharing across multiple applications is also a breeze, which is absolutely key once you get past the "single Rails app" stage and you start getting into two digits worth of tools, services and applications.
* Statically safe metaprogramming.
* Well designed access rights (private, public).
I also really like the type system, very well designed.
Disclaimer: I do not have enough PL type theory under my belt to confidently make this argument.