I hate it when you go to one of those Makerfests, and it actually turns out to be about Makefiles.
Actually is a really good conference to learn Software Development beyond C++
Meanwhile a C conference would have a hard time coming up with interesting content year after year IMO. You'd end up having to talk about how C is used more than C itself, but then you're no longer really doing C-con, you're doing "embedded-con" or "high performance trading con" etc...
I agree with the parent when they compare C to a hammer, it's a super useful tool and I'm glad that we have it but it's not like I could talk about it for hours (or hear somebody else talk about it for that matter).
I don't think there's much of an analog for C. Most of the interesting stuff in C revolves around things you would think you can depend on but actually break in really weird and interesting ways (misc undefined behavior, sizes for integral types on different architectures, idiosyncracies of the preprocessor, the way to trivially exploit that pattern you used to avoid buffer overflow exploits). But most of that is just depressing.