I don't know what the old one was, but let's say it was something like the Ford Courier from the 1970s. That pickup could take a load of 1,400 lb (635 kg). I don't know how often someone would need to load more than 600 kg into their truck, and that's with the curb weight of 2500 lbs or about 1100 kg. A modern F-250 has a curb weight that's more than double the Courier at about 6300 lbs or 2850 kg. It can carry 5000 lbs, (2270 kg) but again, how often is that needed?

I can understand buying a big truck if you're towing heavy things, but for loading up the bed with stuff, I wonder how often someone would get to 600 kg and say "I have lots of space remaining, but dang it, I've reached the weight limit!"