The problem is that people often create languages that are basically the same as existing languages; no new concepts. New languages are usually a grab-bag of features found in C, Java, Lisp and/or Haskell.
> Programming languages are distinguished not by what they make possible, but by what they make easy.
Practically all programming languages are computationally equivalent. The design of a new language simply seeks to answer the question: what should be easy for the programmer? Various languages are just different answers to this question.
There's maybe 3 major islands of languages today. Within each island, they make essentially the same things easy.
The answer to a question like "Python or Ruby?", "C# or Java?", or "Rust or Go or C++?" mostly boils down to historical accident: what system did the original designer pick, which usually means which one just happened to have a good library for the primary goal of the first prototype.
>"Rust or Go or C++?"
Does one of these make memory problems easier to avoid?
>"Python or Ruby?"
One of these prioritises having a single way to do most tasks, while the other prioritises programmer expressiveness (simple example: "unless" is absent in Python). Thus one is easier to onboard newbies with and have them relatively quickly be able to read the code in their ecosystem, while the other allows skilled programmers to convey semantics more efficiently.
I'll admit being mostly ignorant about the differences between Java and C#, but at least in general the languages you contrasted do make different things easier.
Edit: grammar.
Not much.
And yet, whatever they claim to prioritize, they aren't particularly different on those fronts.
OTOH, they have radically different features even if both are dynamic multiparadigm languages, though it's true that decisions between languages often turn on ecosystem rather than language features independent of how different the language features are, and that's also true of Ruby vs. Python.
Haskell is an interesting case because it is a fairly simple language by default (hm type system) with laziness as big innovation. But it also lets you play with experimental features via language extensions. Some work out great, others like implicit nested data parallelism get axed eventually.
With different predecessors, that's also true of at least C and Java on that list.
OTOH, the particular "combination* of features in the grab bag can be quite significant in practice, even if none of three features are new individually.
I bet a true random sample of programming languages would be a lot weirder.
50 programming languages of the last 50 years, illustrated in 50 minutes. It includes all the popular languages, but also covers some truly weird ones.