I don't think the idea that people will use tools to automate generation of CSS is a new idea, nor is it worth claiming the "demise of CSS" over it since it's only a paper-thin abstraction over CSS anyway. People aren't calling web scripting languages "the death of HTML", afterall.

I'm not sure the analogy between languages compiling to machine code is a particularly good one. High-level languages compile to machine code because it's extremely tricky to create or update hardware to support high-level languages, and machine code is especially ugly. Neither of these apply to anywhere near the same extent to CSS, which significantly reduces the advantages of added abstractions.

I'd also be way of calling Sass a "programming language". CSS preprocessor would be more accurate.