Also, through I did not seen it in Scala but in different language, the part of coding I personally enjoy the least was the prolonged fight over which features are going to be used with code reviews being primary tool to force other team members into submission. Seriously, I like following team standards, but new rules suddenly appearing during code review were pretty annoying - giving me a choice between not meeting deadline and following other dude random opinions whether I agree with them or not.
Apache Spark supports 4 languages: Scala, Java, Python and R. Most Spark applications are written in Scala.
Akka is clearly a very successful project, being used widely for very high volume systems. Apache Spark removed Akka because so many users were having version compatibility issues between the version of Akka they were using and Spark was using. Enough people want to use both in the same application that the Spark guys rebuilt Spark without Akka.
I might agree with you regarding Akka Streams ;-)
Scala tries to be everything at once, it's hardly a language of compromises. It was successful because when it was created Java sucked and now of course people are stuck with Scala deployments as nobody can decipher all that code. Java still sucks but less that it used to be. It needs type inference for like yesterday. The biggest drawback of the language is the slow toolchain.
And compared to Oz, I'm quite happy with how neatly unified it has turned out to be. It's not perfect, but as someone who regularly uses both OOP and FP, I'm pretty happy with it. I'm really looking forward to Dotty, because a lot of the cruftier things about Scala can start to go away.
But I think it is complete BS to say that Scala isn't good for "making software". The two most successful projects of my career were relied heavily on Scala to deliver robust product on aggressive timescales, with teams largely composed of first-time Scala users.
You can read one of the stories here: http://artsy.github.io/blog/2016/08/09/the-tech-behind-live-...
I'm not going to tell you that it's an easy language to master. But I do believe it is a fantastic language for making software.