I think there is definately a future for television, it just won't be the same as what we have been used to all these years. The networks may or may not begin to diversify again (the success of Lost and rise in ratings for Alias this year would seem to suggect at least ABC is going to be more open to genre programming again) but the real changes will come via the cable channels, in my opinion.
Coming from the UK i'm very used to the terresterial channels (our equivalent of the networks) being empty of anything remotely considered to be quality television. We have five main channels here (BBC 1, BBC 2, ITV, Channel 4 and Five) all of which have gradually reduced their genre programming to nearly zero. The BBC has pretty much stopped showing anything that is imported from the US, i believe that they are showing Farscape on BBC 3 at the moment but that is it. The awful Doctor Who (and i do mean AWFUL, it's like watching Childrens BBC on a Saturday evening!!!) is by no means worthy of replacing shows like Buffy and the X Files which used to have pride of place on their schedules.
ITV has been that way for as long as i can remember, to the point that i don't even need to use the third button on my television remote control anymore. There is absolutely nothing worth watching on ITV, literally!
Channel 4 and Five do actually show a decent amount of US shows, the likes of Buffy, Stargate and Alias, and other less impressive series like Charmed and The O.C., so they at least get merit points for that.
However in the UK, if you want serious genre programming then you need to pay for the right these days. All the best, most up to date series are only available on satellite or cable subscription channels like Sky One, E4 and Bravo. This has been getting more and more true ever year for the past five or six years as the terresterial channels showed less and less concern for the minority viewers such as genre fans, in favour of mass produced reality shows and soaps like Coronation Street for the sixty years plus audience.
This will be the way things now go in the States, if they haven't already. More people will start subscribing to cable channels because they are not satisfied with what the networks offer. The cable channels will start getting higher viewing figures and therefore start making more money through advertising. This will lead to the like of HBO, Sci Fi and channels like that being able to develop more and more quality programmes which will, in turn, prompt more people to want to spend the money to subscribe.
The networks will realise sooner or later that diversity in their schedules is essential if they want to remain relevant. They will also realise that giving a series enough time to develop a fanbase instead of cancelling it ten minutes after the first episode airs is the only way to guarantee long term faith from your viewers. Whether they realise this before they have lost all their audience is pretty much up to them.