Colin Salmon is a popular actor though and there was a lot of online support for him to replace Pierce Bronson as the next James Bond.
Brosnan, not Bronson. And just how popular is Salmon? What was the last Colin Salmon movie you saw in the cinema? How often has he headlined a big movie? Ever? There's a difference between people going 'Oh, yeah, I like that Charles Robinson guy' when they see him play a supporting role in a Bond movie and actually paying money just to see him as the lead.
He was even called in to do test shots I believe.
Actually, what you're thinking of is the fact that he used to stand in for Brosnan during readings for other actors auditioning for roles in the 007 movies. He never actually read for the role of Bond.
The other movies you refer to aren't really in the same class as a Bond film or Bourne for that matter.
Nonethless, they were sizable hits, whose sequels saw the leads replaced by new actors playing different characters. Ditto, for example, Speed 2, Terminator: Salvation, those Pink Panther movies made after Sellers died. And those sequels all flopped.
Can you name a franchise which replaced the lead character and which succeeded and continued with the new lead? I can't. That doesn't bode well for Bourne.
No one is replacing Matt Damon, he doesn't want to the film after being asked and they're creating an entirely new character with established popular actors.
Read my post again, I didn't say 'replace', I said Damon was a harder act to to follow.' than Vin Diesel, Arnie etc. And that's what will happen. Someone other than Matt Damon will have to headline a movie with Bourne in the title. Damon is associated with Bourne and vice-versa. Many cinema-goers who have loved Damon in the role will walk into the cinema expecting to see him; others will know that he's not involved and give it a miss. He's not being replaced in the role of Jason Bourne but he has to be replaced as the leading man in the Bourne movies and that is an unenviable task.
Finally, at the minute, we don't know if it will be an established popular actor in the lead. Most of the names under contention are far from box-office gold or household names. Maybe it will work out, who knows. Damon was rescued from a dwindling career by Bourne; maybe the magic name in the title will do the same for another young actor. But why not, you know, 'create an entirely character' and totally disassociate it from another actor's signature role?! Wouldn't that be better, free it from The Bourne Baggage (hey, I'm going off to register that title!)?