The thing about Java and C++ is that they themselves are around for historical reasons. Far better languages have already been proven out. But, it will take a major industry player to move the masses forward on this. Apple's Swift effort gives hope on this.
For what they do, C and C++ don't really have serious challengers yet, not that there aren't some promising contenders.
Obj-C to Swift won't happen overnight at Apple either, but it is much more likely to happen because they've been gradually working towards it for years now with LLVM and such.
Only if you define "what they do" in a way that makes that a trivial tautology (e.g., as "things for which C and C++ don;t really have serious challengers"). Over time, a lot of serious challengers have arisen and competed with (and even displaced) C and C++ in areas where those languages have been widely used. There may still be areas where they don't have serious competition, but those areas keep getting smaller.