People here aren't flying in the lower cabins, where the author of the original article mostly seems to be.
The 747 offers poor levels of comfort for those down the back for the reasons you rightly mention. I too want them gone as soon as possible.
Nothing to do with what cabin your are in. To repeat what I said, the 747s are old, loud, inefficient, have dry air, poor pressurisation, vibrations, the list goes on. All of that i completely irrespective of what class you are flying.
Arriving after a 10 hour trip in a 787 will have you in significantly better health than arriving after a 10 hour trip in a 747. It's as simple as that. The 747's, while romantic and old. Just aren't as good as modern planes.