The loyal audiences for daytime TV mainstays like “Dr. Phil” can be potent lures for advertisers frustrated by unpredictability and time-shifting in prime-time. But that loyalty also makes daytime a tough club to break into — a fact proven again this week by the early demise of Katie Couric’s “Katie,” the most-hyped new entry to hit the market in years.

Out of the top 10 daytime syndicated shows, just three were launched in the last five years: “The Dr. Oz Show,” “Steve Harvey” and “Katie,” whose ratings ultimately couldn’t justify its costs. That’s not for a lack of contenders. Last season’s freshman fatalities included talk shows from Jeff Probst, Anderson Cooper and Ricki Lake.

But once a show gets established, it tends to stick around. The No. 1 show in daytime syndication, “Judge Judy,” has been on the air since 1996. “The Ellen DeGeneres Show” has aired since 2003, Dr. Phil” has had his own show since 2002 and “Maury,” No. 6 in daytime syndication, bowed in 1991. The longest-running daytime syndicated shows were “The Phil Donahue Show,” which aired for 26 seasons, and “The Oprah Winfrey Show,” which aired for 25 seasons.