Good point. I suppose ACD's Watson would have earned some money from the books (just as ACD did!), but there's no income from the blog - just free publicity.
I don't think the blog is up to much though, not enough up dates, not a terribly engaging style, etc. It's more like a personal blog than for publicity, but I suppose that was originally the point (for John).
But yes, I think the archetypal Holmes and Watson, how we imagine them, is sharing the flat, working together, and not really having much room left for other people. Hopefully we'll see that again soon.