Wilder actually did cast Gloria Swanson as Norma Desmond because she was a faded silent star from Hollywood's silent era. I don't think you could intentionally make another Sunset Boulevard today. And if you did, it would have to contain a lot of allusions and homages to real life.
Sunset Boulevard was littered with homages and nods to Hollywood's forgotten past.
Nicole Kidman!!! I read in a French magazine two or three years ago that she was the frontrunner for the filming of the musical!!! Nicole can sing and she actually looks frozen/mummified by now!!! Natural choices like Streep or Glenn Close have become far too old for the part!!!
Glen Close actually played Norma Desmond in the stage production of Sunset Blvd. While its not nearly as good as the movie or anything I think it's cool that you mentioned her pretty quickly and she did technically have the role.
It's a pretty brutal business. One minute you're a goddess, the next you're desperately hanging on in the hope that you'll get to come back in a support role as somebody's wise aunt or mother.