And just as many people are the "casual" fan, who would much rather see Venus Williams play, regardless of whether it's taped or not, and don't really think about it being taped. Next year, take a look at the commercials that are played. They're not all tennis related, they aren't all "sports" related, they are quite often geared toward the "soccer mom", who is at home, and might stick around to watch because she likes to see Venus play. Or Andy Roddick.
And I think you're being somewhat naive to say that because they pass up on Carlos Moya, they're not promoting tennis. American casual fans, the ones who don't visit steveg, don't know about other tournaments outside of the majors, would much rather see Roddick and the Williams sisters than some guy with a funny name.
If you want to talk about golf, look at the coverage of the British Open this year. First of all, ESPN does play highlights of the Open during the afternoon. And they play it live. Notice who they focus on....Tiger, Phil, all the Americans. It's also a completely different setup, just because of the fact that 85 players are all going at it at once. Tennis is just a different beast.