Why should they move forward? They put their TV where they want to have it, and sit where they feel comfortable. It may look better if they're sitting 8' from a 50" TV, but if they're 18' away and not getting the full benefit of HD, should they redecorate to allow moving closer?
Would you argue that people who buy 4K TVs need to move even closer, and closer yet again when the 4K market is saturated and TV makers start trying to push 8K? People either won't have enough room to get off their couch without bumping their TV, or they'll need a TV screen so large they'll need to raise their ceilings to make it fit!
I am merely saying that to get the maximum benefit from an HD picture, one should not sit too far back, so much so that one's eyes cannot possibly resolve the detail that they just paid to see. I haven't seen the math on a 4K TV or at what point diminishing returns obtain. The issue isn't necessarily moving up or back, it is, however, sitting at a distance where one can derive maximum benefit from one's purchase. Anyone can sit anywhere they want by choice, it would be nice if it were an informed choice. (and in the cases I referred to in my post, they were not informed and experienced a dramatic improvement after moving closer to the display. The object is to help people get the most out of their investment, not just pander to the status quo in order to make a comfortable sale.
In the cases I was describing, they did NOT put the TV "where they wanted it", they put it where it had been with no thought to the consequences. After working through the issue with them, they changed their viewing distance and were quite happy about it. The assumption that people buying HDTVs know what best suits their needs is, in my experience, more often than not, wrong. A little considerate help goes a long way in satisfying customers.