Some will say Rust, but we're years away from that being realistic. C++, using modern techniques, is perhaps the only feasible response.
While there may be some validity to your claim about "billions of human beings wasting hours" due to vulnerabilities in C code, we can't forget that the alternatives would also suffer from significant forms of waste.
If using a language with slower runtime performance, for example, people will need to wait longer for their computations to complete. More powerful, or even just more, hardware will be needed to alleviate these delays. Slower runtime performance also often results in much higher energy consumption. The costs just keep adding up and up.
Forcing billions of people to use far less efficient software, while requiring far more powerful hardware, on a continual and ongoing basis, for decade upon decade, could very well generate waste that far, far exceeds that of dealing with an occasional flaw in widely-used C code. I just can't seriously buy your "All the performance benefits ever derived from writing everything in C has been more than erased, by orders of magnitude, by the damage caused from even simple innocent mistakes." argument.
C won't be going anywhere until somebody provides a practical alternative that offers benefits without any downsides. It's as simple as that.