I've always struggled to believe the claims over fire regulations.
Last time I flew with BA to Japan, I noticed how much more comfortable the seats on board were compared to the IET I'd just used to get to the airport! The crux of the matter here is that, pound for pound, I would wager the aviation industry is much more extreme wrt fire regulation than even the railway. Not to mention that aviation seats have to also be as light as humanly possible, and will typically be in use for >14 hours at a time.