The 747-8 Intercontinental is more than 12 percent lighter per seat than the A380
Even if this statement would be an engineering statement, and no marketing statement (called lie before political correctness became popular), it is still half of the truth.
Of course a structure designed and certified per 1960s rules is much lighter than a modern one. Different crashworthiness requirements, damage tolerant structure, larger rapid decompression hole size, different uncontained engine failure rules etc. costs weight and gains safety. Of course a 1960s Renault 4 is lighter per passenger seat than a 2006 Renault Megane, but would you buy one today, if you could ? Even if it would be equiped with a 21st century fuel economic engine and tinted glass windows ?