Good point, Wunwing, but maybe only if the cargo volume (and/or the payload available with 100% passenger L/F) per passenger seat has been increased significantly over the years.
The older aircraft also had much of what you describe, but not roller beds as I recall, which along with special cargo doors were found only on cargo aircraft, or combis, and I suspect that's still true.
I'm not sure that power distribution for freight handling purposes is a big weight factor on passenger aircraft.
But I'm sure you are right, and the volume and payload available for freight with a full passenger load could well have increased, thus keeping the total empty weight per seat where it was. Do you have any numbers? I don't.