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In that case, I disagree. Anime certainly requires attention, and, heck, the same can be said for cartoons, but live-action stuff isn't the same case. Unlike anime, which is a largely visual experience, live-action television isn't so much. When I watch anime, I take in its quirks, animation, cohesion, artwork, so on and so forth. With live-action TV, though, it's not the same case because there's no need to leave a constant visual impression on the viewer. Though the backdrops do play a role, ultimately the role of the visuals in live-action, among other things, is to keep you feeling like your watching a show (aka immersion).
And it certainly differs from show to show, and what a specific person feels about a specific show, but I'd find it understandable if someone split their attention between...I dunno, their computer and DLTMS0-relevant shows like BBT (ohgod). And if someone is truly invested in an experience, they'll drop what they're doing and just watch. But focusing entirely on a show, especially one that is meant to be watched casually, really eats away at ones time. Not to mention reruns and casual background TV are a thing. But not all TV is meant to be this thing that forces you to commit to it, that's just the nature of television.