No they won't. DoD is small compared to the rest of the software market. You get better quality and lower cost with COTS than with custom solutions, unless you spend a crap ton. The labor market for software's no different.
Everyone likes to crap on C++ because it's (a) popular and (b) tries to make everyone happy with a ton of different paradigms built-in. But you can program nearly any system with it more scalably than anything else.
Go was built because C++ does not scale. Anybody that's ever used a source based distro knows that if you're installing/building a large C++ codebase, better forget your PC for the day because you will not be using it. Rust also applies here, but at least multiplatform support is easier, so I don't fault it for slow build times
> more scalably than anything else
That's quite debatable. C++ is well known to scale poorly.
In my experience people criticize C++ for its safety problems. Safety is more important in certain areas than in others. I’m not convinced that you get better quality with C++ than with Ada