I know almost nothing of these games. So, can you please tell me where this is referenced there?
I always found Akuma killing Bison to be a bit anti-climactic: So, you have one fighter make it to the final battle and then Akuma just jumps in and kills Bison? How are Guile’s, Cammy’s and T. Hawk’s endings supposed to happen now?
Especially Guile’s one only works if Bison is already defeated. I cannot imagine Guile just stepping up to a perfectly fine M. Bison and threating to kill him with his family stepping in and stopping him. This only works if Bison is defeated, either by Guile himself or by the tournament winner.
They should have made it in a way that you fight Akuma without him killing Bison. This way, the story line could be devised in a way that Ryu and Guile made it to the semi-final, but Ryu drops out of the tournament because he feels Akuma’s presence. This way you can make Guile the official tournament winner who defeated Bison, but with the big climax of the story being Ryu vs. Akuma.
But the way it was presented in the game: Imagine you had to create an anime based on the game and you were supposed to create your story in line with the things you see in the game (i.e. don’t invent completely new stuff like in that aftermath trailer): How would the ending work out?
You could create it in a way that Ryu makes it to the final, then Akuma kills Bison and Ryu fights Akuma, sure.
But how could Guile and the others get a satisfying ending? It would feel a bit strange:
“Dammit! I lost. Well, I guess I’ll have to confront Bison after the tournament. Let’s just hope that Ryu defeats him. Oh, nevermind. That sinister guy who is dressed and moves just like Ryu killed Bison. Hm. Fair enough for me.”
“Honey, don’t do it.”
“Jane?”
“Don’t kill Bison. Killing Bison won’t bring Charlie back.”
“Nah, don’t worry. Look: Someone else already did the dirty work for me. Let’s go home.”
There are basically two canons now:
The old one where SFA3 and SF2 are two separate events, where Charlie died in SFA3 (and was, without a doubt, dead and Guile accepted it) and where Bison really was killed by Akuma in SF2.
And the new SF4/SF5 canon where SFA3 and SF2 have been merged into one event, where Charlie’s “death” scene was the one from SFA2 and where Bison’s demise is similar to the countless SFA3 endings, but where he was fought by his enemies as they appear in SF2.