Regardless of the cost, the history of the franchise and the diminishing returns from 1987-2005 along with the current state of television ratings makes it seem unlikely (note I'm not saying impossible) for Trek to make a return to television.
The history and ratings from ten years ago aren't really that relevant today. And just because TV ratings are down doesn't mean that there isn't a shift to other markets like streaming.
Star Trek could be financially viable in the right market, but there are several other factors holding it back.