I think that CBS' late night shows, more than any of the network's other programming, are losing out by not being on Hulu, or another app/service that reaches Roku, Chromecast, Apple TV, game consoles, etc.

The company's business model to limit their shows to their own website, and selling next day episodes on iTunes, Amazon Instant Video and other VOD services works well with their prime time series. However, I believe keeping Letterman off Hulu has hurt the show as the younger demographics turn on Fallon, Kimmel, Colbert, etc more often since the Late Show is not an option.

And now, with Colbert taking over the Late Show in 2015, keeping the show off set top boxes would be damaging to the segments of the audience that currently watch "The Colbert Report" via Hulu.

Update: In October 2014, CBS launched a Hulu-like service called CBS All Access, which made its way to Roku in April 2015.