I've never bothered to actually get a dedicated tv.
You sound young.
First of all - I have a wife and kids, I have a hard enough time using my own computer as it is, I have to target times when they're less likely to be around demanding my full attention - which is pretty much any time anyone plus me is home - except for my oldest who can fend for herself. (the wife and toddler both want lots of attention)
Second - I do have a nice 27" 2560x1440 monitor, and I have watched high def content on it. Were it the only screen in the house I would have a hard time taking either Cookie Monster from my toddler or the Gilmore girls from my wife to reply on Slashdot, I get the stink eye for not not focusing attention on them for any amount of time as it is.
I'm Gen-X, I'm guessing anyone Gen-Y or older probably has a TV that predated the easy to do everything on one screen era, which didn't truly start until the introduction of HDMI in 2006. Sure, I hooked a TV into an ATI Rage card back in 1997 and I built my first MythTV system back in 2003 using a Haphaug card.
If I were 22 and living in my parents basement there's a pretty good chance I wouldn't bother with a TV either. Really - my plans for an office is to get ~50" 4K TV, mount to a wall over a desk, put a couch against the opposite wall. That way I'll have a good gaming setup and a good computer monitor in my own space, but I'll still going to have something else in the living room - you know, because I don't want to rule over my family on a throne while they live like servants.
As for game consoles - I go back a ways. Sure I'm emulating a bunch of old consoles, and I guess I could part with any console that has a good enough emulator, and probably should, I just have a hard time actually doing it.