Raw's rating troubles are likely due to a combination of factors. Wrestling is not in a boom period right now. The move to a three-hour marathon ensured it would be a real challenge to keep fans invested for that length of time. The star power on the roster is pretty thin and there are way too few fresh match-ups available. Monday Night Football is back and offers strong competition most weeks. Additionally, the start of a new season for popular shows such as Castle probably siphons off a reasonable number of viewers.
For wrestling fans, though, it may really boil down to overexposure of the product and the recognition that anything of significance that happens on Raw can be seen recapped on Smackdown, on the company website or at the intro to the next ppv. We now have the new Main Event show on Wednesdays, Saturday Morning Slam and NXT on HULU.
How much is too much? And when does more become less interesting and important? Despite the common misconceptions and stereotypes, most pro-wrestling fans do have lives and can't afford to watch wrestling every waking moment, even if they wanted. They are also discriminating enough to pick what wrestling is worth watching and when.
In the territory days, a show each night of the week from different areas of the country featuring the various personalities of each promotion's top attractions could probably keep the interest of many fans, but watching the same roster of WWE superstars interacting endlessly on shows with different names on different channels is simply cutting the same pizza into smaller slices.