That's why I included Swift. Now that it is going to be open-sourced and available on Linux, it will - hopefully - become a good replacement for Go / etc. Will have to see how the community evolves, of course. Currently I use Go in certain situations but I'm hoping to eventually be able to replace it with Swift - will just have to see how things progress.

Disagree though about Ruby being icky at scale. Whilst some companies have moved away from it as they have gotten bigger, there are tonnes of companies that are still using it successfully.

I also disagree that the other languages cover Ruby's uses. It is an incredibly flexible and powerful language and has an incredible assortment of very well written and very well maintained libraries - far exceeding any other language I've used. Plus, having used many other web frameworks, I'm afraid nothing is as good as Rails. Some, such as Django, come close - but nothing quite beats it.

That said, it all depends on your use cases. I'm mainly a web programmer, building web apps, APIs and the occasional mobile app. I'm not dismissing other languages by any means, but these are the languages that I would personally keep if I had to throw away my knowledge of all programming languages but three.