The History Channel hasn't been remotely interesting (or history-related) in years.
Even in the early 2000s you could tell that the channel was about to go downhill.
That's the only time I ever watced it, so I can't really comment on that.
Most of the theme cable channels have pretty much lost their theme by now. You can occasionally still find healthcare on Discovery Health, but that's it.
Everything else is just a 24 hour cycle of Real World and Diners, Drive-ins, and Dives knock offs.
USA's managed to stay vague enough that it's actually pretty good.