Agree with all this, especially the movies that you point to that would probably be in contention from this year. Are the 70s movies listed higher because of nostalgia for the critics that are getting older, are they measurably better movies than the top movies from 20 years later, is it a function of people having 20 more years of watching those movies so they are ingrained in the culture more? Interesting discussion for sure.
Also factored in is I purposely left out if these lists are people's favorites or what they think are the best (if there is a difference). If I had to list he greatest movies ever or most influential, sure stuff like Godfather and Chinatown would be popping up. If I am listing a desert island movie ranking, I am probably grabbing Fight Club over Chinatown for my island.