David Cohen, Executive Vice President of Comcast, recently described Comcast’s mammoth operation in simple terms using the 80/20 principle. 80% of Comcast is their legacy cable and cable related businesses--phone, internet, home security, he said. That is still Comcast’s financial bread and butter. Of the remaining 20%, 80% of that slice is largely Comcast’s interests in cable networks, USA Network and many others. The smallest piece--20% of the 20%--was NBC. NBC is important, but it is small stuff in the overall financial picture.

However, Mr. Cohen wisely said, with no specific statistics but with logic behind him, that small piece NBC generates 80% of the Comcast publicity and buzz with burning societal issues, among others:

1. Will Comcast rename the Rockefeller Center building?

2. What’s wrong with The Today Show? Has America grown tired of Matt Lauer?

And today’s question, What’s the late night plan post-Leno? So, what are those plans, we ask?

Didn’t NBC just go down this path a few years ago? Of course they did. Conan was going to take over. He did—ever so briefly—but they kept Leno in the wings by giving him a 10pm show nightly. That didn’t work, so they brought him back and gave Conan his walking papers. It wasn’t the smoothest orchestration, but the decision netted stronger ratings than any alternative to date as Leno, love him or not, has continued to deliver audiences, albeit older ones, which are critical to ad dollars.

However, Back to the Future: NBC’s latest plan is to move the younger Jimmy Fallon, 38, into the Tonight Show by the fall of 2014 and to shift the show back to New York from Burbank.

Will it work? Maybe? Will they do it this time? Probably. Will Leno,62, rise from the ashes yet again to return? Probably not next time.

As with all media types, forms, and day parts, change has been the status quo. The dominant Johnny Carson late night era has been dead for years. The reality is that late night television is a fragmented day part with many entertainment options, including cartoons and sports.

Advertising is the key criteria for success and Leno still leads the pack financially and in overall ratings. But Leno’s audience skews older while cable viewers of Jon Stewart and Conan tend to be younger. Financially, The Tonight Show is now longer a financial bonanza with less than $50 Million revenue generated annually, a big drop from the $150 Million Leno used to generate.

The landscape is competitive with David Letterman, a longtime rival on CBS, and now Jimmy Kimmel on ABC (See previous Monitor: Kimmel, Earlier). Kimmel is building his new 11:35 audience, is stronger in a younger 18-34 demo, and may soon surpass Leno is the 18-49 demo as well.

What will Leno Do? Fade into the sunset? Take a full time Vegas gig? Or will he “take his talents” to FOX as it is rumored?

The answers will unfold in the weeks and months to come. NBC may be a small piece of the Comcast overall empire, but as David Cohen knows, the spotlight shines brightest on the biggest entertainment names.