Almost unnoticed? Green Day were pretty big in the California punk scene. The thing is that they were in an independent label, so they couldn't reach a lot of places. And just before Dookie they went to a major label, and since those times they are called "Sell Outs" (that also happened to The Clash), but they did that because they sold so many records that the capacity of their independent label couldn't manage it. Kerplunk! (1992) is one of the best selling independent albums of all time. So they didn't go unnoticed, they were actually very popular. One thing is going unnoticed and another is you not knowing what happened. That album sold 50,000 copies at the time and is now Platinum. The only reason Green Day is not very respected is because they are considered "Sell Outs" for being in a major label and for painting their faces for American Idiot (many punk bands and proto punk bands have used make up). That is artistic expression. I will make a comparison with what happened to Metallica. They were called sell-outs for their "Black Album", but the truth is that that album brought a lot of attention to the genre and to a lot of other bands. That's what Green Day did. The difference is that GD keeps making quality records and stays relevant.
And as I have said before, Ramones were punk-pop. Just listen to their songs, and read the lyrics. Songs about love, about wanting to be a girls boyfriend, songs like "Let's Dance" that is the cover of a Pop song. They take a lot of surf-rock. So if we're trying to make an objective list, GD should be way up higher from where it is now. There are a ton of bands in this list that take a lot from punk-pop. The success of GD with Dookie alone allowed a whole generation of bands to be commercially succesful (Offspring, Blink182). Sure, they're not well regarded in the punk community, but it is influence. Why should influence on hardcore punk be more important than influence on punk-pop? It shouldn't.
Well, maybe almost unnoticed was an exaggeration, but I still don't think their pre-Dookie era work is very important when looking at punk as a whole. It really was "Dookie" that put them on the map for most people. "The difference is that GD keeps making quality records" is nothing but your own personal opinion and therefore completely irrelevant for this list. They may have stayed relevant as a commercial force but what they're doing stylistically now is far from groundbreaking, and also pretty far from punk. The only Green Day albums that became major critical successes were "Dookie" and "American Idiot", the latter being closer to alt-rock than actual punk.
The Ramones were not punk-pop in the 1970s. Punk largely developped from 1960's garage rock and the Ramones added a lot of surf rock to the equation, that's true. They also covered 1960's pop songs and all that made them important and influential on the development of punk-pop, a term that wasn't used until the 1980s. But the Ramones also had a different attitude towards their music than many of the 1990s pop-punk bands had. The Ramones were decisively anti-mainstream, singing not only about wanting to be some girl's boyfriend, but also about drug (ab)use, beating the brat with a baseball bat, a.s.o. I'm not trying to say here that 1990s pop-punk bands should not be considered punk at all, I'm just trying to express that it would be historically wrong to categorize the Ramones as punk-pop.
Now finally let me say again that Green Day was very very important for the development of punk-pop and that they influenced many bands on the outer fringes of punk and they should definitely be rather high on the list and that's exactly where they are.