The vast majority of currently-airing shows are available to view on-demand. They're just not always available in the format you want. Generally, shows availa

The vast majority of currently-airing shows are available to view on-demand. They're just not always available in the format you want. Generally, shows available to purchase on DVD are also available to purchase as season passes on for-pay services like iTunes, Xbox Video, Google Play Video, and Amazon Instant. Same goes for back episodes of current seasons. Hulu also has some shows(from a few networks) that are in-season but have fallen out of the cable service on-demand window. The exception to this rule is sports (which are a whole different can of worms) and shows on "premium" cable networks (HBO, Showtime, etc.) which require you to pay a separate subscription to watch anything in-season before it's released as a box set or as a for-pay stream.