I don't know, exactly, but I know with some confidence that C++ has never had significant uptake among ops and systems people. The folks who build systems, run systems, and dip into code on occasion to make the systems run, but not as their full-time job, have never (to my knowledge) fallen in love with C++. They probably all know some C, Perl, and Python...maybe not a lick of C++ (except the "C" part).
I think C++ may just be too rich a language to be a part-time thing. I think Rust might have the same problem (though I'm finding it easier to read than C++, it doesn't seem to be afraid to require a lot of learning time from its developers). But, I'm willing to entertain other theories.
For whatever reason, Go seems to have very quickly entered that category of language that systems and ops people are comfortable with.
I agree that rust will have an adoption problem amongst part-timers. Rust code is unreadable until you spend a few days with it and writing it requires a week or two of wrestling with the borrow checker.
In contrast, one of the reasons I'm a big fan of go is it is extremely easy to read for almost anyone. People pick it up very quickly.
I can only speak about my own experience as an ops person, but C++ always just felt off to me for some reason. I tried to learn and use it for about 6 months and I always felt like I was so bogged down in minutia and standards.
C let's me focus on the underlying system and it is what Linux is written in, Python is quick to write and has great libraries, and Go is amazingly easy to pick up/read.
C++ always felt like it was more so a language designed for programmers who love code than something that lets me focus on what I love (systems).
Better C++ than Go or Rust. Antecedents and track record counts. Young people like the new thing. Go and Rust are capitalizing on that. Learn C. Take the time..it takes a
couple years and some pain to learn it and then you will be amply rewarded. These languages (go|rust) are reactive and suffice for some purposes but they really kind of suck in every other possible way.
I'm old(ish), have worked professionally with C, and I think I have to disagree with you. Certainly, learn some C; it's the language on which all of our platforms are currently built.
But, building new things in C? Nah. I don't see any reason for that. Since C was designed, we've ("we" as in our industry, not specifically me and you) learned a lot and our systems have grown massively in all dimensions. It would be optimistic to assume we don't need different tools 40+ years on.
C++ looks good on paper. It has containers and types and generics. You come to find out that it's all based on meta-programming which is an interesting idea: Basically you're writing code to write code, and that code writes code. The whole system is macros all the way down. There's no native language support for anything but macros and the macros implement everything.
The student's experience is that he can quickly solve a problem using a list of stacks of strings (vector<stack<string> > > in the parlance.) Which is fine, almost like typed-python until you make a mistake. Then, the compiler, who knows nothing about those types which were all built by expanding macros, is not your friend.
Miss a minor `*` and a single line of code will fully expand its underlying macros giving a 10-page, indecipherable error message.
Should you make it to runtime, no debugger can tell you the contents of a vector, string or stack. They're just blobs of buffers and pointers with mangled (and yeah, that's the word that they chose: mangled) names to make them extra unreadable.
This is when most people ask if they can just have C back.
In C, I could not find good libraries for basic stuff (dynamic string manipulation, variable-sized arrays, hash tables). I tried glib but it was much worse than C++'s STL.
It is entirely possible to write C-style programs in C++ (very few classes, globals all over the place) and so on, and at least for me, C-style software in C++ are much safer/easier to debug than C-style software in C .
In my experience the C mindset is to write those yourself. The lack of templates means that it's very difficult to write proper generic containers. You either end up with macro soup, void * soup or code tailored to your needs. Or a lot of the time a combination of all three.
But I'm like you, if I know that I'm going to need "advanced" data structures I'll pick C++ over C (or these days more likely Rust).
To go along with this, due to overloading and inheritance rules you cannot look at a small section of C++ code and determine what it does without reading up to the entire program.
I think that holds for any program written in any language. If the abstractions are confusing then it will be hard to read, be it layers of C macros, over-use of template programming or bad class hierarchy. BTW C++'s standard library is mostly functional (having roots in scheme), which makes it pretty easy to reason about.
I think C++ may just be too rich a language to be a part-time thing. I think Rust might have the same problem (though I'm finding it easier to read than C++, it doesn't seem to be afraid to require a lot of learning time from its developers). But, I'm willing to entertain other theories.
For whatever reason, Go seems to have very quickly entered that category of language that systems and ops people are comfortable with.