Ok your arguement has value and merit, but remember young people don't watch news, or television. Young people are getting news from social media, or watching from their phones, tablet. If they're watching news. They will not sit for an hour or 30 minute newscast. They may watch a minute clip. Now, you can't dismiss the 35-49 demographic viewer that more educated, and more consumer savvy, and income more stable. Also the consumer who grew up watching that same station with their parents/ grandparents. That brand has stand out for generations.
Again, you said some dated logo & slogan from 70s serving as their brand, but let look at WSB/Atlanta- Coverage You Can Count On slogan since 1991. #1 station in the market.
WCVB/Boston, WATE/Pittsburgh, WISN/Milwaukee the Hearst station have had the same logo since the 70s, but they've just kept their news fresh and kept up with the times.
WXYZ/Detroit another Scripps station and the circle 7 been there for along time when it was owned by ABC. Yes, it been modifed but circle 7 is very synonymous with WXYZ and their brand.
McDonalds brand is the golden arches it been modifed over the years. Since 1971, Nike had the swoosh, and different versions. A girl with freckles and pigtails is the Wendy's brand. There are some logos that have been with brands for decades now. They've just modifed/refresh with new color, but the brand has kept up with the times.
WEWS/Circle 5 and First in Ohio....The first tv station in the state and the market. It maybe old, but it has defined their brand for decades. For Cleveland market the states biggest market. No, it not in the top ten. Des Monies, IA had the same logo on their Channel 5. Whoever said yes to WEWS logo thought it was the cat's meow, but it doesn't define WEWS' brand and looks cheap IMO.