What took them so long?

Herewith, a cursory round-up of items, all of which can be responded to with a simple, “What took them so long?�

And what took me so long to compile this? The blog’s server has been down or near meltdown all day.

The Nielsens will finally include measuring the viewing habits of college students in their ratings, which will give a good number of shows – think “The Daily Show with Jon Stewart� and “The Colbert Report� – tremendous ratings bumps.

Hard to wonder why this didn’t happen a decade or more ago, given how valuable the 18-49 demographic is to advertisers, and the low end of that demo has perennially been almost impossible to lure – or, at least, measure, since so many of them are, in fact, in college.

Former GE uberlord Jack Welch (sort of) explains NBC’s Jeff Zucker’s failing upwards:

Key exchange:

Q: If NBC isn’t doing so well, why is Jeff Zucker still in his job?

JACK: ’Cause I’m retired.

ABC is mixing up its Wednesday comedy schedule, with “Knights of Prosperity� and “According to Jim� flipping timeslots.

That’s a no-brainer: Anyone with just a little TV programming experience will tell you that you never, unless you have absolutely no choice, lead off an hour with a brand-new sitcom. (That probably helped prod “Big Day’s� premature exit, and accounts for why Fox’s “’Til Death� has underperformed all season.)

But the main reason for the switch is to protect “Knights� from the “American Idol� juggernaut. “According to Jim,� having run longer than anyone expected, is more deserving cannon fodder.

Hence, ABC’s new Wednesday lineup: 8 p.m., “George Lopez;� 8:30 p.m., “Knights of Prosperity;� 9 p.m., “According to Jim;� 9:30 p.m., “In Case of Emergency;� 10 p.m. (returning Feb. 7), “Lost.�

CBS has gunned down its D-List cop reality series “Armed and Famous.�

What is it about that 8 p.m. Wednesday timeslot? Nothing seems to be working there, except “Jericho,� which returns Feb. 14, and it’s not like “Jericho� is huge. But every show in the timeslot only manages between five and eight million viewers, pretty pathetic numbers.

Until “America’s Next Top Model� returns, and, bolstered by the new ratings reports from colleges, goes through the roof.