If you genuinly are too out of shape to sit on a floor then maybe you should take my joke advice for real. Sitting on the floor is not supposed to be a test of strength but...maybe it should be?
Hahah thanks for your advice wise one
My issue with sitting on the floor is a matter of comfort, not ability, as my knees/ankles and most other joints are pretty much gone/shredded to bits. I am not obese or incredibly fit, but I am not going to sit on the ground to relax and play videogames, esp not for a lengthy session of any sort, and not in my game playing area that has a concrete floor.
Good on you for wanting to be miserable all the time, that's very admirable I guess, I'll stick to my recliner or couch when I am enjoying a relaxing session of game playing 
This is a similar boat I find myself in as well.
Can I sit on the floor? Sure. To a degree.
Do I need proper lumbar support?
More then I need to sit on the floor.
Why? Having sever lumbar issues as a result my work in my twenties and early thirties has turned my back, hips, and knees into basicly mush. Maybe Zeta doesn't have a spine that has curved due to intense physical abuse and can sit on the floor on his head. However, for me I need lumbar support and choose to use the furniture and available tools to make gaming more comfortable.
This means I would most likely utilize a cable extension is some sort of I were to utilize the mini NES at some point. Provided my initial concerns and controllor cable length are correct I. That they would not reach from my tv to the couch.
Could I put the system in the floor and have cables and what not lengthened to accommodate? Sure. If I didn't have a 1 1/2 year old who enjoys grabbing anythjng with in reach that is t bolted to the ground or outside his reach and walk through out the house with it in hand. Granted I greatly enjoy just chasing him around the house as he giggles smiling all the time trying to run and hide from me with what ever controllor, game, book etc he managed to grab and hold to.
Ok off topic.
Zeta just calm down with the gross generalizations all the time. You have such a pessimistic view of things all the time. It's great to have an opinion, however, must you always go and use such tackless ways of articulating your views.