That's the average cost of a sci-fi film with top production values but I believe that includes the promotional marketing costs. Terminator Salvation's quoted budget of $200 M is apparently before marketing costs. You notice the TV ads for TS4 have now become non-existent? That means they don't want to pour any more money down the hole -- they need it for the foreign market and it's now going to become a cash flow drain.
Of course, the cost is dependent on the actors they hire, the CGI effects, the sets, and that's after they've paid the writer(s) and the director (who is often on a percentage rake-off status as I believe Christian Bale signed on for). I don't see them getting a film like Star Trek's production cost below that figure.
