Compared to web development, those communities you mentioned are very closed to most people. With Javascript, there's no special equipment needed, and you can pretty much just pick it up and go...there's tons of freely-available knowledge in blogs, and open source code to read/get involved with.

Where's the github for assembly line firmware code? I would be very interested in learning more about other non-web-development domains, but it seems like unless you get hired right out of school to program something like cars or satellites, you're pretty much shut out forever.