The academy has a hard job. How exactly can a group of people evaluate movies that are totally different from each other and choose which one is the "best"?
What is best?
Revenue?
Attendance?
Artistic quality? (how do you measure THAT?)
Technical quality?
Social significance (Should this even be a criteria?)
Amount of gratuitous nudity (I added that in

)
Bribes/Payola?
Movie "stars" in it? - A term I use very loosely.
Public opinion?
There are movies I like and there are movies you like. Which movie is "best"?
Well, generally I feel that the better movies are the ones I like, but the problem is that there are others who apply the same criteria but from "their" prospective.
I put very little credibility on what some group calls "best". Movies are an art form and as with every other art form, every viewer has the right to like it or dislike it and everyone else has the right to ignore what other people think of it.