Not sure about conferences, but what bothers me is that there is no single acknowledged discussion group about C, after Google destroyed newsgroups and comp.lang.c with it. There should be a very popular Reddit sub about it, but yet Reddit is not enough standard among developers, unfortunately.
I'm unsure what you mean by Google "destroying" newsgroups. Newsgroups were decentralized to begin with, the fact that Google purchased Deja News and then didn't... I don't know, turn it into a Reddit-equivalent or something doesn't surprise me. You can still use Google Groups as a Usenet gateway and there are still other Usenet gateways around, although the offerings are getting a bit more scarce and it's no longer a standard part of your ISP's package.
Whenever I look at places like comp.lang.c (which still exists) I remember the bad Usenet experiences I had in the 1990s. It's certainly not worse than it was, in my mind. If anything killed newsgroups, it was Slashdot / Reddit / Stack Overflow and the like.
Maybe "killed" is a strong word. My feeling is that when Google exposed that part of the internet to the web, it became interesting for spammers to target USENET much more than in the past, which was a very strong contributing factor for USENET to die. Moreover once no longer an "hidden gem" many felt exposed posting to USENET, now that it was trivially web accessible.
My feeling is that the web was becoming larger and more accessible every year, and that while Google probably did that more than anyone else, you could equally blame AOL for providing NNTP access to the general public in 1993, or Deja News for starting their archive work in 1995, or Google for their indexing work starting in 2001.
That's just assigning a name and face to economic forces, though. It's the underlying economics that killed Usenet—experts hang out there, so it’s valuable, so non-experts start hanging out there, until the experts leave because there are too many non-experts. This happens to every internet forum; Usenet was just older. Travel back in time and any randomly selected person on the internet was likely to be some kind of expert.
Yes, what you say surely makes a lot of sense. Maybe there is to start some form of forum that is very unpleasant to use, like, just having a command line interface to access it... and vim as editor :-D
Right now there is:
* https://www.reddit.com/r/C_Programming/
* https://www.reddit.com/r/c_language/