A paintbrush is indeed far more important than the painting of Michel Angelo or da Vinci from an historical point of view.
On top of that, there are thousands of programming language today, many relying deeply on concepts and paradigms that are much younger than C itself, but C remains one of the most used languages. Not only C is very much used, it's still the only option in many cases and it is by far, the language that is most used to implement other languages, or at least to bootstrap them.
Considering the age of the paintbrush comparing to, say, spray ink, your analogy is in fact, not only valid, but a very good one.
No, it isn't. Da Vinci used a paintbrush to paint. Steve Jobs did not use C to program, because he never wrote any code or even designed anything according to at least one verifiable source[1].
It's more like saying the paintbrush is more important than anything some really successful art dealer ever did.
