I wonder what intrinsic quality makes a language long lived, rather than blame communities and whatnot.

Another stalwart is Pure Data, the DSP language I am very fond of. It's based on atomic principles. Indeed the primitive processing elements are called Atoms, being irreducible ops like multiply, add, sin and cos. There really isn't much that can change. For C as for LISP, especially Scheme, it's hard to break them down any further, yet they are high enough level to be useful for programming. There's some sweet-spot to be found.