Internet content delivery is limited only by bandwidth, not resolution. The pieces are in place, the codecs can handle the image dimensions, content is already being produced at excessive resolutions, delivery channels exist, the only thing missing is trustworthy display hardware at a viable price and a public willing to buy in.
It's not quite that simple. Resolution is only one part of the picture equation. When it comes to delivering content over the internet, the provider has to make some sacrifice to picture quality to fit it down the pipe to get it to you. If it were as simple as you make it out to be, we'd be streaming 2+ hour Blu-Ray quality movies off of iTunes as we speak.
But we're not. And if we can't stream Blu-Ray quality movies via iTunes now, what makes you think we'll be able to stream even higher resolution media next year? To put it in perspective for you, streaming 480i DVD quality media to over the internet requires a connection somewhere in the neighborhood of 6Mbps. That's a 640x480 freaking interlaced DVD. You know. Where every other horizontal row of pixels is skipped. Oldschool stuff. We're only now getting to the point where that quality of a connection is widespread (in America at least).
Broadcast HD eats up roughly (I believe) 16-20Mbps of bandwidth to stream through to your house. Getting that over the internet isn't out of the ballpark for most people living in metro areas and suburbs. But what about Blu-ray? As in uncompressed, what you see when you pop in the disc quality? Well, lets do some simple street math here to find out (Someone correct me if I"m wrong. Math ain't my....gooder).
Lets assume most Blu-Ray movies are about 30GB, and last about 2 hours. To stream that live without any buffering period would mean that, yup, you have to download 30GB in 2 hours. That's about roughly 35Mbps right there. That's high end, expensive cable connections, or entry level fiber. Not very many people have access to those speeds. And that's at 1920x1080. 2560x1440 will be even more costly to download uncompressed. And what about people with download caps? Well, I guess Canada is screwed. They'll just about eat up their monthly allowance on one movie alone. Sorry, Frosty Brothers and Sisters of the North! I think you gotta sit this one out.
So here you all are, wanting to spend the cash on a TV that is capable of displaying an ultrasharp picture at higher than HD resolutions, but you don't have any way to get the content to the screen to justify it. Well, other than buying a Blu-Ray player. But disc based media is dead and all that.
So no, the delivery channels don't quite exist for the mass market to justify making a TV higher than 1920x1080 just yet.