I'm of an age were I can remember those magnificent cutaway drawings in the Eagle boys' paper which dropped through the letterbox every Wednesday. The future would apparently be filled with airliners of increasing size and levels of comfort. Two ubiquitous features on all of these projects, apparently, would be a walk-up bar and a grand piano in the spacious first-class lounge.
In practice, of course, once the airlines get their hands on these airframes, like tract-housing, its just a matter of squeezing as many people into the available space as technology and user-tolerance will permit. If Boeing did make their fuselage 20cm wider (and, by implication, deeper), then the someone, somehow, would find a way to squeeze in a 12th row.
"Recliner on the mezzanine, Sir"?