My favorite western. It deserved to win on its own merits, regardless of Clints earlier work.
Also it’s a movie about westerns. To the Academy, made up of people who are heavily involved in movies, that might resonate a little more then with the population at large. That probably helped to give it an edge as well.
I like Silverado but I have major problems with it. It seems to me that Kasdan made a movie that was about an hour too long, then he had to cut it. Some of the plot threads went no where, particularly Rosanna Arquette’s.