You can say that about every technique that goes 1 level lower in abstraction. Personally, these techniques allow me to write the vast majority of my code in a high level JVM language (Scala in my case) and optimize the very small percentage of my code that needs to be this latency sensitive.
Because I can get so close to native performance in that highly specific case, the idea of using C++ hardly ever comes up. If I need faster than this, C++ is probably not fast enough either and I need to look at "closer to iron" solutions. I for one appreciate that. But then again, I'd much rather program in C than C++.
As far as claims like Java is 3x slower than C++, it is nearly impossible to quantify these things directly. For any given benchmark you will be able to find people who complain about the code in the benchmark not being optimized enough.
Suffice it to say that there are some things Java is faster at and some C++ is and their are techniques in both that allow them to achieve near parity.
Because I can get so close to native performance in that highly specific case, the idea of using C++ hardly ever comes up. If I need faster than this, C++ is probably not fast enough either and I need to look at "closer to iron" solutions. I for one appreciate that. But then again, I'd much rather program in C than C++.
As far as claims like Java is 3x slower than C++, it is nearly impossible to quantify these things directly. For any given benchmark you will be able to find people who complain about the code in the benchmark not being optimized enough.
Suffice it to say that there are some things Java is faster at and some C++ is and their are techniques in both that allow them to achieve near parity.