C++ is one of those "does everything" languages. You can do everything from high level, garbage collected code, down to inlining assembly. The level of explicit control and setting up your own abstractions is really powerful. It comes with very high shoot-yourself-in-the-foot potential, but most people don't accurately assess that cost.

I'm sure other languages or combinations of languages will be able to supplant C++ eventually, but the combination of inertia and some of C++'s niche capabilities, plus its extensively optimized compiler support, makes C++ just a generally hard language to replace.