The negative performance impact of GC in performance-engineered code is neither small nor controversial, it is mechanical consequence of the architecture choices available. Explicit locality and schedule control makes a big difference on modern silicon. Especially for software that is expressly engineered for maximum performance, the GC equivalent won't be particularly close to a non-GC implementation. Some important optimization techniques in GC languages are about effectively disabling the GC.
While some applications written in C++ are not performance sensitive, performance tends to be a major objective when choosing C++ for many applications.
While some applications written in C++ are not performance sensitive, performance tends to be a major objective when choosing C++ for many applications.