Economy seats in narrow-body mainline planes, which operate the vast majority of domestic seat-miles in the US, have been the same width for over 60 years now, since the Boeing 727 commenced commercial service. Leg room has definitely declined, though.
I long ago quit thinking of air travel as fun or enjoyable. I decided it’s basically a flying bus.
In videos, passengers appear to be squeezed into the plane like sardines in a can. Flying was practically a glamourous experience years ago. I have not set foot on a plane in a long time.