For a lot of problems performance really isn't the problem. In many, many cases the engineering cost to optimize C++ to get a benefit over Java / C# will be way more expensive than just paying for more servers. Even in game dev where milliseconds matter C# is very common.
Personally I agree about dynamically typed languages not being great for large projects but that's more about maintainability than perf.
Personally I agree about dynamically typed languages not being great for large projects but that's more about maintainability than perf.