Old people with bad eyesight watching their 50" 12 feet away in their big ass living room vs young people with good eyesight 5 feet away from their 65-70" playing a game might have inherently differing opinions.

12’ 50" FHD = 112 PPD

5’ 70" FHD = 36 PPD

The study basically says that FHD is about as good as you can get 10 feet away on a 50" screen all other things being equal. That doesn’t seem that unreasonable