During the 747's design phase, Boeing hedged its bets on its passenger potential, put the cockpit up on top [in the famous bulge], and hinged the nose on freight versions to allow front-loading.
The double deck A380 does not have that flexibility.
“During the 747’s design phase, Boeing hedged its bets on its passenger potential”
The freight capability must have made the 747 more expensive. Nevertheless they sold a bunch of them for passenger use. Impressive, huh?