Good languages are local maxima in the language design landscape. C is a good language. As is Python. And C#. There are many projects for which C or Python or C# are fine language choices.

Other languages have great ideas in them, but the languages themselves are a mixed bag. Perl, Java, C++. Perl inspired Ruby. Java inspired C#. But we haven't seen a good successor to C++ yet, probably because building a systems language is much more difficult than building an interpreted/scripting language.