Just to nitpick, TBS is still WTBS. They are a brodcast station here in Atlanta. They just don’t advertise the W that much anymore. For example, during the Braves playoffs they played ESPN’s feed for the games, and had their little WTBS symbal in the corner of the screen.
I would imagine that they care a lot, but there isn’t a lot that they can do to prevent losing their viewers to, for example, USA network. Or, well, there’s one thing they can do, which is try to deliver content that they think a lot of people want to watch.
As far as commercials, sometimes all you can do is pick a time to run some ads and hope for the best.
If CBS loses you to USA, they are losing you to NBC. USA Network is owned by NBC Universal. Competition between the networks extends to all of the subsidiary cable networks as well – for ABC that includes ESPN and the Disney Channel, for NBC it’s CNBC, MSNBC, Bravo, and SciFi, in addition to USA, and for CBS (Viacom) it’s pretty much everything else, including UPN, MTV, Nickelodeon, TVLand, SpikeTV, VH-1, Showtime, The Movie Channel, BET, and Comedy Central. All of these subsidiary networks have a stake in synchronizing their commercials, and frequently do, which is one reason why you sometimes find only commercials on every station.