But is that really so silly? I used to work in front of a computer. I was sited all day and I can tell it got very uncomfortable. I had back pain and stuff. Now I spend most of my time on the bed, and my back is absolutely fine. The main drawback is my neck, but it's not nearly as inconvenient.
What I mean is : isn't the posture what is wrong with sitting instead of just inactivity? If so, does that mean we need something like the Altwork Station[1]?