I'm not at all surprised that BBM got nothing at the SAG awards. Why?
1) Williams and Gyllenhaal are blazing new stars, but they're new. Great work got them noms, but their competition (esp. in the actress part) was formidable. They're both overcoming being 'child stars' in less-prestigious roles (Proof wasn't even noticed, sadly).
2) Ledger (I'd bet money) was a close second to PSH, not a far behind second place. Still, PSH has a larger body of critically acclaimed work to draw on for prestige and 'deserves it'. Sadly, awards are given for those reasons, not sheer acting ability alone, not based on objective criteria, or even on work within one year, or one film. Ledger may still be doing penance for "A Knight's Tale". ;-) Ledger deserves the Best Actor Oscar; PSH (and JPh) did imitations, evocations, much like Jamie Foxx in "Ray". Exceptional and gifted acting, yes, but still more homage and stunt than building an original character.
3) Ensemble Cast could not have gone to BBM; in fact, I wanted Crash to win. Crash is a stunning film, and it is an ensemble piece; it's an actor's movie, and as such, was a lock for this type of award. BBM had a *great* cast, but it was not an ensemble piece. It was Ennis and Jack's movie, with ancillary (if wonderful) characters appearing occasionally. This should not keep it from winning best picture.
Still, I'm predicting 4 Oscars (Picture, Director, Adapted Screenplay, and if the academy has a brain, Cinematography or Score, maybe both). An award for Ledger would be icing on the cake, but it's unlikely, and frankly, I'd rather see this film get Best Picture.
People will go see it for that, not for 'Best Actor'.
-backtobrokeback