The cabinetry was much lighter. My '65 Globetrotter overheads and closets are made with 1/4" veneered plywood that weighs very little. The galley cabinets are 1 X 2 hardwood covered in the the same thing.
New cabinets are more of a solid wood and are very heavy in comparison. Shower doors. microwaves, multiple speakers, desks, gray water tanks, bigger fresh water, 2 axles, rock guards, 2 TV's, VCR/DVD, Sat dishes, real mattresses, solid surface counters and more....it all adds up.
-"You want to make it two inches - or, if you're working in centimeters, make sure it's enough centimeters for two inches."-Red Green