Smallville is one of the only bright spots on the network this season. Even if it's ratings weren't performing as great as the are, I don't think WB could afford to cancel Smallvilel anyway. Especially with the news that 7th Heaven is going off the air after this season. Smallville is the only other consistent performer for The WB.
From Variety:
http://www.variety.com/article/VR1117932804?categoryid=14&cs=1&s=h&p=0
'Heaven' takes final bow
WB skein ends in its 10th year
By DENISE MARTIN
Long-running family drama "7th Heaven""7th Heaven" will wrapwrap at the end of this season.
The WBThe WB announced Thursday it was retiring the skeinskein after this, its 10th year. "7th Heaven" launched in 1996 and grew into the web's signature show and was often its most-watched hit.
While "7th" is still a solid ratings performer, because of the skein's age, its costs have risen steadily over the years, making it cost-prohibitive for the Frog to continue production, insiders said.
Still, show consistently draws more than 5 million viewers in its current season, among Frog's top-rated shows.
"Although we had anticipated this could be the last season, it was difficult breaking the news to the cast and crew," series creator Brenda Hampton said. "At this point, we're all very much a family. However, just like the Camden kids, I think we've all grown up and it's simply time to leave home."
"We owe a compelling and unforgettable final season to the Camden family and to the millions of viewers who helped grow this program into a huge hit," entertainment prexyprexy David JanollariDavid Janollari said.
"Not many shows make it to 10 years and it's even rarer for a series to go out on top after 10 years," exec producer Aaron SpellingAaron Spelling said, thanking the WB for putting on a family show "when it wasn't very cool to do so and then sticking with it in the same timeslot for the entire run of the show."
Hampton exec produces with Spelling and E. Duke VincentE. Duke Vincent.