I've just been to visit my sister and it got me thinking about this. As a deliberate choice her living room has no sofas/armchairs. She's got a kitchen large enough for a wooden table and chairs, and then there were 2 other smallish downstairs rooms that have been knocked through into 1 bigger room and it's pretty much entirely floor based. It feels a bit studenty at first tbh but the more I think about it the more I like it!
There's lots of cushions/beanbags that they move round the room depending what they're doing. There is a large coffee table that they often eat at, a TV corner, and a sort of reading nook. All at floor level. She's also got some low wooden stools that double up as moveable tables. She WFH most of the week and sits on the floor to do it. Her (teenage) DC do their homework, art, board gaming etc sitting on the floor. She is in her early 50s and is up and down off the floor about a million times a day, and it really shows in how easy she finds it!! She was telling me about how one of the key things as you get older is to make sure you get get yourself up off the floor because it can save your life as an older person.
I don't think I could give up my sofa 🤣 but it did make me think about how little I get up and down off the floor and that I should do it more. I did it more when my DC were little, obviously, but as they've grown up it's not something I need to do very much.