> But because the plumbing must be laid out so meticulously and in every situation, it is often hard to see how things work at a high level. You can't see an architectural sketch in Java, you can only see endless classes in endlessly nested subdirectories. This is a very low level of abstraction, and helps the layperson (such as someone approaching a new open source project) build up an understanding from the base elements. But what's lacking is the high level abstraction.I agree that it becomes tricky to get an overview of the whole project in C/Java/etc, but I very much disagree that it actually becomes easy to get that high level overview in Scala/Ruby/etc. As soon as the project becomes 'interestingly large' and full of the corner cases that comes with interacting with reality, all languages fall down here. Regardless of the level of the language, you are still communicating with a machine. I'd guess that for a mathematician who has spent most of their lives looking at equations and little time talking to people, a mathematical functional language may seem easier to read than a novel - but for most people this isn't the case.
The best way I've seen to handle this regardless of language is to have the high level overview outside of the code in a human form document describing the reason for components and not just what they are.
This is also why I prefer simpler languages (like Java or C, as you say) - they are very good at specifying exactly what is going on with little room for creativity to confuse things. We use legal contracts for a reason - imagine if our laws were written in poetry? Writing a computer program is much closer to a law than a poem as you need to limit ambiguity as much as possible and specify as many corner cases as possible to prevent undefined behavior. Plus being at a lower level means optimization strategies are easier to see.
There's a reason C/Java/C#/etc are still the most popular languages, imo. The only real outlier being Javascript which gets its popularity from being the only option for the browser.