That's fair. But I don't think it's reasonable to lump learning about lenses (or other abstractions that aren't part of the prelude) into learning Haskell.

Judging the ecosystem is fair in the same way that Java is lumped together with the reams of j2ee, spring, AbstractFactoryFactory sort of libraries that it yields.

For better or worse, switching to Haskell does entail asking yourself how hard it'll be for your team to become comfortable with things like http://learnyouahaskell.com/functors-applicative-functors-an...

That's a good point. I suppose people do judge Java by the popular Java libraries and their styles. However, I don't really consider those things when talking about how difficult Java is to learn.

Learning Haskell may well be easier than using it, although the same is true for most languages.

But you don't learn Java just to learn Java, usually. You learn it in order to solve a problem. Which means working with the ecosystem. And personally, I'd rather use libraries I can understand if needed.

Except that lens is being used by a quickly growing chunk of the ecosystem:

http://packdeps.haskellers.com/reverse/lens

(Yes, I am guilty too, but I inherited the dependency via Chart ;).)