The padding was probably a lower percentage of the volume, because they were honkin' great cubes to start with, but don't try to pretend that LCDs in boxes come to the same size as (or even remotely comparable to) equivalent-viewing-size CRTs in boxes.
The other thing is that TVs are nearly trapezoidal prisms, but the boxes are nearly cubes. There’s a lot of dead space to fill with some structure, especially if the boxes need to be stackable.
So did CRT TVs.
The padding was probably a lower percentage of the volume, because they were honkin' great cubes to start with, but don't try to pretend that LCDs in boxes come to the same size as (or even remotely comparable to) equivalent-viewing-size CRTs in boxes.