I've taken several passes at Scala but the thing that always stops me is that I find it really hard to read unfamiliar code, including the core API implementations. The only Scala code I find easy to read is impure semi-object oriented code which is the non-idiomatic code that the Scala community tries not to write. I'm not sure if there's some point at which a penny drops and it all starts to become easy, but even if that is true, the time period it takes for that to happen is a real hurdle for newcomers.
To me, you have to be intrinsically motivated to become productive in Scala because of that early friction. Which is fine if you are, but if you're looking at a team of programmers and thinking "how do I get them all over that line" when about half of them have no intrinsic motivation to do that, it's a real disincentive to use the language.
To me, you have to be intrinsically motivated to become productive in Scala because of that early friction. Which is fine if you are, but if you're looking at a team of programmers and thinking "how do I get them all over that line" when about half of them have no intrinsic motivation to do that, it's a real disincentive to use the language.