So... a band that started in the underground punk scene in Berkeley and released their first album on a tiny indie label at the age of 18 is supposed to have the same exposure as bands who were signed immediately to major labels and released their first albums on those labels?
Your logic is stupid.
You can hate Green Day all you want, that's certainly your right, but you can't really argue with the effect they have had on other bands in the 90's and 00's. Hell... I'd love you to poll 100 people and ask them which album was more influential: Dookie, Shake your Moneymaker, or Facelift. Dookie blows those out of the water.
GREEN DAY'S first major label record had 5 singles, is rated DIAMOND, and has sold over 20 million copies world wide. It was an album that inspired millions of people to pick up a guitar, go into their garage, and start bands. Ask any band that came out in the 00's if they had Dookie growing up. Oh... and this happened when Punk rock (whether you think Green Day wasn't hard enough punk) did not make you any money.
American Idiot has sold over 15 million copies worldwide and again inspired many kids to hit the garage again. It made Green Day one of the largest bands in the world AGAIN.
Record sales?... check, Grammy's?.... check, influence?... check, longevity?... check.
EDIT: Sorry... Billie was 17 and Mike was 16 when they released their first album.