It's a darn good movie
Simple as that.
Great visuals, great characters, great actors and acting (Hagman excepted) and a great storyline. And the picture is nuanced to a degree they rarely risk today in mainstream movies.
Frankly, I'm amazed at how critical some of the posts are, concentrating and dissecting minor flaws in the film.
Perhaps IMDb makes us so intent on looking sharp in our observations that we sometimes lose track of bigger and more important points -- like how good the movie is.