Maybe simplistic old school graphics and 2D art just tend to be more quaint and interesting than new quasi-realistic 3D games filled with dead doll eyes and shiny skin?
My seven year-old niece dislikes modern 3D games and animation, yet loves NES games and old Warner Bros. cartoons.
Regardless, calling a Larry game "classic" is a stretch.
I wasn't even aware they had 'trailers' for games back in those days. And is it really right to call your game 'groundbreaking' when you're basing it off a preexisting text adventure?
I discovered Leisure Suit Larry when I was 13 and looking for porno games on the (then fairly new) internet. I remember copying a pirated LSL1 to a floppy and giving it to a classmate. He later told me that he threw the disk across the room after failing to get past the age check questions.
Other than KQV were there any games in the series where you could do something wrong in the beginning and screw yourself over later on? Because that is a lot worse than some annoying animal friend.