Personally I pretty much just watch Youtube, DVD's or Stream these days. I only ever put the tele on as a background thing when friends or family are here as sometimes it's easier to channel hop than find something specific to watch.
I think that a huge number of people do still watch TV, either due to age, technical knowledge, or just lack a good internet collection or physical library. My parents have recently started streaming pretty much everything as their internet has gotten decent enough to actually stream video. They do still channel browse or pop a DVD on if the internet sucks, but it is becoming more common.
I get the feeling that will be the same case for many more people as internet speeds get faster and more widespread, as well as smart TV's or smart boxes become cheaper and more common. We are a way's off TV becoming obsolete, but I think traditional channels are certainly on borrowed time. Many channels here in the UK have catch up services online these days, and the BBC have made it so you need your TV licence to access their site. To me that says there has been a definite impact on channel based viewing.
