C++ is a language designed to enable more communication between the compiler and the programmer.

Go is a language designed to enable more efficient communication between programmers.

C was hardly efficient in the 80s micro-computers, and outside Bell Labs people were doing compiler optimization research in languages like PL.8 and similar.

Had Bell Labs been allowed to sell UNIX and history would certainly looked much different.

For instance, Fortran is very performant in numerical computing, even outperforming C, but it has difficulty in accessing I/O mapped registers or implementing an interrupt handler, a jump table, or just cleaning a particular chunk of memory addresses.

"Oh, it was quite a while ago. I kind of stopped when C came out. That was a big blow. We were making so much good progress on optimizations and transformations. We were getting rid of just one nice problem after another. When C came out, at one of the SIGPLAN compiler conferences, there was a debate between Steve Johnson from Bell Labs, who was supporting C, and one of our people, Bill Harrison, who was working on a project that I had at that time supporting automatic optimization...The nubbin of the debate was Steve's defense of not having to build optimizers anymore because the programmer would take care of it. That it was really a programmer's issue.... Seibel: Do you think C is a reasonable language if they had restricted its use to operating-system kernels? Allen: Oh, yeah. That would have been fine. And, in fact, you need to have something like that, something where experts can really fine-tune without big bottlenecks because those are key problems to solve. By 1960, we had a long list of amazing languages: Lisp, APL, Fortran, COBOL, Algol 60. These are higher-level than C. We have seriously regressed, since C developed. C has destroyed our ability to advance the state of the art in automatic optimization, automatic parallelization, automatic mapping of a high-level language to the machine. This is one of the reasons compilers are ... basically not taught much anymore in the colleges and universities."

-- Fran Allen interview, Excerpted from: Peter Seibel. Coders at Work: Reflections on the Craft of Programming

The reason why older languages are complex and inelegant is because our understanding of how to create simple yet useful languages has increased, not because older languages accumulate much complexity.

One of the big differences is that Java and Go have straightforward context-free grammars, mostly, and you can whip up a working parser in no time. C++ is a bit of a beast, by comparison (hence keywords like “typename”).

C++ also has the complex overloads and template system. I think people underestimate how complex these things are when they are learning C++, and how complex their interactions are. Then there’s the preprocessor.

You can kind of argue that these are just an accumulation of changes, but other languages contemporary with C and C++ do not suffer from these complexities, so the argument falls flat. By comparison, Go and Java rely on reflection or code generation more, and these are a bit simpler.

And then there is arcane stuff like this:

* https://en.cppreference.com/w/cpp/language/eval_order

* https://en.cppreference.com/w/cpp/language/copy_elision

That does make the language feel very complex even without the whole templates depth.