Well, revenue drops would trail behind major interest drops due to the nature of broadcast rights contracts, but if networks pay a ton of money to fill slots with stuff people aren't watching, eventually they go under.
I don't think baseball is any kind of a boom period right now, but I see the deals teams like the Dodgers, Phillies, Rangers, etc are getting for their local TV rights in the last couple years and I have to think these cable companies believe people are watching. I also see league-wide attendance in the vicinity of historic highs, and so the only thing that seems to be suffering right now are the national broadcasts, and I chalk most of that up to the saturation of market with national broadcasts over the last decade or so, and the general downward trend in TV ratings overall.