In terms of advertising revenue, I can't guess at fixed numbers, but it seems likely that the rates are inversely proportional to the price of the comic. If you buy a comic for four bucks, that has to be to compensate for something. And that makes sense.
(For what it's worth, looking up newspaper advertising, with a couple of wild four-digit aberrations, a column-inch doesn't generally go for more than three hundred bucks. The overwhelming majority are less than twenty, which seems to also generally be about the price for papers in smaller, affluent areas that might match comics. Does a column-inch match a page? Do we need to find out how many column-inches to a page? Anybody want to just call DC or Marvel in the morning?)
Now, best I can figure bumbling around the Internet, it looks like page rates are roughly a hundred dollars per page for a typical nobody writer/artist. So, figure it costs somewhere on the order of eight thousand (script, pencils, inks, each at a hundred for twenty-five-ish pages, plus miscellaneous worker bees and a cover). It could be lower, but it's also higher in cases where you hire a superstar type, so that seems like a good starting point.
For printing costs, I see estimates (from Mexico, which sounds like a good lower bound) of about thirty cents. And Diamond gets a 60% cut (I thought they took more--I come from a world where every middle-man takes half the profit, so expected more like 75%). That leaves DC or Marvel with somewhere around $1.30, assuming their printer (Quebecor, was it?) can match the Mexican prices.
Assuming all of that is right, and ignoring advertising for the moment, a book needs to sell somewhere around six thousand copies to break even. That seems like a more convenient unit of measurement than trying to guess how much money is "good." Every extra six thousand issues moved is a failing book that could be floated for another month, basically.
Also consider that office space in midtown Manhattan is about seventy bucks per square foot (advertised, so assume higher after some bait and switch), which is equivalent to about fifty comics sold. I'm not saying that DC covers that cost, but rather that Warner could get that much by booting DC out and renting the space to a shady hedge fund, so they should ideally make that much money. That means that the 32k originally cited, minus operating costs, allows them to cover the equivalent of rent for roughly ten standard office cubicles (32k - 6k, /50x50).
Advertising-wise, I'll hazard a guess that the rate for a full page can't be much more than a thousand (figuring the above column-inch of twenty, times 6x10, gives $1200), so ten pages of advertising is another four or five cubicles (or two books that can be floated).
It's not a terrible business to be in, but as Roy points out, that's less revenue than before inflation, and the direction isn't suggesting much growth.
