But why do people insist on being able to do low and high level stuff in the same language? What's wrong with, say, using Python for high level stuff, and calling into C for low level tasks? C+Python is probably more convenient than C++.
I should have said "there is no other language which gives you the latitude for crafting high performance tools". You can indeed create serious high performance systems in a number of languages. The thing about most languages other than C and C++ is that things written in them tend to inherit their qualities - A system written in Java generally use Java's garbage collector. That works great for a number of things but it's still a constraint.
More of C++'s "modularization" features are optional than in the other languages so you have more latitude for creating your tools than anywhere else.
Of course, you do get the badness too...
Have you worked on it? Do you know this? Is it all written in Lisp, or are the parts that need high-performance and predictability written in C or C++?
There's a lot of language FUD out there. I say this as someone who owns OnLisp, and has spent a lot of time learning Lisp.
The seriously complex and high-performance ITA system is written in Lisp.
And if you read Coders at Work, some of the criticisms of C++ suggest that the reason behind many of the C++ features is that Bjarne didn't want to say NO.
And I am happy to leave that particular niche of badness to C++ its own self.