4k and Ultra HD is beneficial on large sets, projection systems and/or those that sit really close to their TV. On sets that are about 50" and below with average distance, the technology's advantage is minimal. Most folks have less than 50" screens and sit far enough away that upgrading would be mostly a waste of money.
In order for the technology to take off, the masses would need to accept it. Most folks are perfectly happy with their current HD set and would not bother to upgrade because it is not that big of a jump in performance. Only those who are videophiles and purists will want (need?) the technology. In general, SACD never appealed to the masses ("CD is good enough and not worth upgrading," says Joe six-pack) - same situation.
Lack of content will surely have an impact as well.
In order for the technology to take off, the masses would need to accept it. Most folks are perfectly happy with their current HD set and would not bother to upgrade because it is not that big of a jump in performance. Only those who are videophiles and purists will want (need?) the technology. In general, SACD never appealed to the masses ("CD is good enough and not worth upgrading," says Joe six-pack) - same situation.
Lack of content will surely have an impact as well.