before The Usual Suspects rocketed Spacey into mainstream consciousness he had supporting roles in films of varying success. who from "The Rocket Gibraltar" and "Working Girls" do you remember with ease without looking at IMDB? not Spacey huh? but he was there. ever heard of "The Ref"? good film, great cast, but hardly anyone remembers it. that was the first film i remember where he was one of the lead (although Dennis Leary headlined it). my point is that you cant suffocate talent in mediocre films/ roles. what Spacey is reaping now (the awards, the plum roles) is result from years and years of hard work on stage and supporting roles in films.
having said that, what makes you think that Schreiber is just some guy who looked like a comic book character and nothing more? other than Manchurian Candidate, you dont have on your list the other work where Schreiber showed his acting chops: RKO 281 (the Battle over Citizen Kane), Hitler: The Rise of Evil, even smaller roles like Sphere, The Sum of All Fears, The Sunshine Boys, Kate and Leopold.... if you've never seen the Citizen Kane flick or Hitler movie then i strongly suggest that you do. Schreiber is at the stage where Spacey was 20 years ago-- did some good roles, most are largely forgotten. but if your'e really paying attention on movies where Schreiber shines, you know this is a man that has talent, that deserves to have a Usual Suspects type of break. he certainly is on the right track-- he's already done writting and directing a film at his age (Everything is Illuminated). Spacey only got around to that a couple of years ago (albeit he admited it took decades to get it onscreen, and only through his fame)
you're putting too much value on the hollywood awards system. just how many actors have won the golden trophy but doesnt deserve it? how many more actors deserves it but hasnt even gotten a nomination?
oh and i may not be a casting director, but i was against Jenniffer Garner being cast as Elektra and Jessica Alba as Sue Richards (renamed Sue Storm sheesh

). dont even get me started with Clooney as Batman or Halley Berry as Catwoman. i have nothing against them other than they just dont fit the role. but they were cast and the rest is history.