Rome was initially meant to be a miniseries of sorts. If HBO can do it, why can't network TV? I think the real problem isn't that it's not doable on network TV, but that network TV doesn't have the structure to encourage such efforts. I think it's a case of, "If you build it, they will come." If you're offering marginal product, you can't expect to get strong ratings. But if the product is good enough and hits on something people really want to see, they'll watch.
And if they watch, you get good ratings. And if you get good ratings, you can charge more for advertising. And if you can charge more for advertising, you can afford good content. But if you interrupt that chain anywhere and, for instance, say, "Instead of spending the nice ad dollars on excellent entertainment, let's allocate a bit more of it to management bonuses and shareholder profits, and pay a little less for the content," then eventually the audience migrates away and you can no longer afford to take big risks. Or if you do take them, they're even riskier. Among other things, you're now trying to lure back a disillusioned audience.
HBO has also done Band of Brothers, and is now going to do The Pacific (among others). The key is picking something that many people would be interested in. How about a no holds barred miniseries written by a good writer, directed by a good director, and starring a bunch of talented (but not necessarily costly) actors. If it doesn't come off like an after school special, I bet many would watch -- all over the world. The problem is, if network TV did such a thing, it'd be a fluff piece. There's too much PC-ness. They wouldn't really show the negatives of the people involved, but that's where thh drama is.
Fair and balanced doesn't make for good entertainment. Roots didn't make sure they showed white people saying slavery is wrong, even though there were many such people. Because the story wasn't about those people. The Shield doesn't spend time showing there are many hispanic people who are decent, law-abiding citizens. Because the story wasn't about those people. The Wire didn't worry about showing the upstanding Cosby-esque black people of the world. Because the story wasn't about those people.
There's so much drama in Obama's rise to the White House that it makes me want to become a writer just so I can write the story. There's how many people on both sides feel Colin Powell was a sell-out (for supporting the war in Iraq on one side, for supporting Obama on the other). And it just goes on and on. You could even through Edwards into it at this point. And McCain/Palin. That story could easily fill, say, 8 hours of TV, and if done right, I see it as compelling. But without a no-holds-barred writer and a no-holds-barred director, it would have no chance of being done right. It'd come off more as a movie of the week. I wish someone like David Chase would do it, but yeah... not happening.