In a non-trivial amount of cases I think this incessant adding of features to paper over old mistakes or fill gaps is actually counter-productive and turns into users having to learn several things instead of the intended situation where you end up just learning the new thing. I've done 7-8 years of C++ and there was definitely a moment where I could work on pretty much any C++ code base in the world at least somewhat comfortably, but I wouldn't take a C++ contract now and then ramp up to it because there's absolutely no telling which C++ this contract would entail and which landmines it has as a result.

Languages that are much more clear about what they support and what they don't support don't have this ambiguous language profile that constantly-appended-to languages have, because they've ended up taking a stance on what they actually do and as a result it's much easier to simply work with what's there. Rust is doomed to be in the former camp but luckily we have much more sensible alternatives to both C++ and Rust nowadays that look to be much more of a known quantity at some point.

Edit:

I also think it gives a language a special kind of funk where it's fairly obvious that certain things were just not all in all a great choice; you end up needing extra features that really only exist because you have other features and so on. `Pin`[0] in Rust comes to mind; it's something that has no intrinsic value and only exists to paper over the mistake of moving around memory magically.

0 - https://doc.rust-lang.org/std/pin/index.html