I'm not sure I understand what you mean by the actual big fish in the market. Google's Q2 16 ad revenue was $19.1B, NBC's was $2.1B, CBS's was $1.6B, and ABC's was also $1.6B.
I was thinking verticals as a whole, not individual companies. The budget for TV, print, radio and so forth tells the size of the market, the fact that there are more players in these verticals than in online search is maybe yet another reason to attack them rather than Google.