He was one of the characters in Sesame Street. Kids probably found his appetite for cookies amusing. The way he talks and the sound he makes when he eats (omnomnomnom) probably made him seem really funny too. And he's as cute as can be too.
The cookie monster is known better than lady gaga by kids and adults so the COOKIE MONSTER
Cookie Monster
cookie monster
cookie monster
Cookie Monster
Cookie Monster!!
cookie monster
cookie monster
Cookie Monster!
cookie monster because he has been around longer.
Harry Potter is way more famous than cookie monster.
Sonic the Hedgehog is better known to both generations so Sonic the Hedgehog is more famous than Cookie Monster