I think it really depends on definition.
Hence my very first question. "What kind of great?"
The top 50 films of all-time are more than just "great" to me (could be more or less, but that's a good #). I would call the top 10 films masterpieces. Probably even the top 20.
This is one of my problems, I'll agree. "Great" seems to be the default term to label everything, all Top 1,000 films. I'll agree that something like masterpiece is more appropriate, but I think it's a bit of a disservice to label films as great when they do have vastly different "great" qualities.
Top 1,000? Well, when you look at the entire history of film and how many have been made, 1,000 really isn't some crazy amount to think are "great". But different people have different definitions.
As an example, I would say Blue Velvet is a great film. But in no way would it be in front of SoTL. Still a great film to me. Different genres, different times, lots of things change what films look like year after year.
It's hard to limit a specific # of movies that can be labeled "great" and then they have to go to being "very good", then "good", etc. And it doesn't take away from the films in front of them. Now, if comparing exact genres and premises, then we could talk about which ones are great or not.
Obviously you missed my rants on trying to find "the way to determine greatness in film." It's sprinkled throughout any posts of mine about "great films," or what have you. But I really think there's SOME esoteric way to determine greatness.
I always ask the question "Why is Casablanca still well received?" I just find it hard to believe that it's JUST emotion. Is it cultural subconscious? Is there a formula for greatness that can be applied?
Interesting questions to ask.