Why not? What is the going rate for Primetime ads on NBC, CBS, ABC etc.? That's just US TV market, there is print and internet advertising, international marketing, distribution costs etc. 100 million Worldwide expenses for a mid-budget movie is pretty standard these days. Even for small movies, the cost of marketing is typically in the $20 million range. Kevin Smith didn't even try to sell his movie "Red State" to studios because the production cost of the movie was less than $5 million and big studios don't buy movies unless they are willing to mount a $20-25 million ad campaign to support it.