All four of our older kids (all in their own homes) have one, or more, Non-Cable-TV "boxes" that are capable of providing video to their tv sets. And our youngest is still in college, & thus doesn't count yet!
My guess is that this will become more common as the younger generation(s) reach the age where they have their own homes, apartments, or sufficient disposable income (or family influence....) to choose their preferred video delivery devices / methods.
Most of our friends who are in our age group (obviously greatly advanced
), are still running "traditional" cable or AT&T U-verse (no FIOS in this area yet), with a handful subscribing to one of the satellite services.
Still, our newer HT arrangement, featuring a Pan blue ray player & plasma tv, does provide "Streaming media" access through Panasonic's "Viera Cast" service, which means access to Amazon VOD, YouTube, and a number of other content providers - although "Viera Cast" is built into either the blue ray player or tv (or both), so no extra "third party" box is required. (And, of course, other HDTV manufacturers are touting their own built in streaming media features.)