Technical advances in special effects (animatronics, liquid and foam latex) meant the human frame could be distorted to grotesque new dimensions on screen. This coincided with the decadent and materialistic aesthetic of the 1980s. Having it all was important. Showing it off was paramount.
Horror movies of the 1980s were also blessed with an audience that wasn't as survival- or firearm-savvy, as so many viewers are now, after being at war for decades and after witnessing so much chaos in the American streets. The coveted suspension of disbelief needed from an audience was easier to obtain.