Note that this is not just my vision of how to get published in journals. It's my vision of how to do philosophy.

Your vision of how to do philosophy suspiciously conforms to how philosophy has traditionally been done, i.e. in journals. Have you read Michael Nielsen's Doing Science Online? It's written specifically about science, but I see no reason why it couldn't be applied to any kind of scholarly communication. He makes a good argument for including blog posts into scientific communication, which, at present, doesn't seem to be amenable with writing journal articles (is it kosher to cite blog posts?):

Many of the best blog posts contain material that could not easily be published in a conventional way: small, striking insights, or perhaps general thoughts on approach to a problem. These are the kinds of ideas that may be too small or incomplete to be published, but which often contain the seed of later progress.

You can think of blogs as a way of scaling up scientific conversation, so that conversations can become widely distributed in both time and space. Instead of just a few people listening as Terry Tao muses aloud in the hall or the seminar room about the Navier-Stokes equations, why not have a few thousand talented people listen in? Why not enable the most insightful to contribute their insights back?

I would much rather see SIAI form an open-access online journal or scholarly FAI/existential risks wiki or blog for the purposes of disseminating writings/thoughts on these topics. This likely would not reach as many philosophers as publishing in philosophy journals, but would almost certainly reach far more interested outsiders. Plus, philosophers have access to the internet, right?