Not at all the same. Jack Ryan existed as a character in print before he was transferred to the big screen. And his was a fleeting appearance that made no big impression on the culture at large.I don't quite agree. That's like saying that Alec Baldwin was the only actor who could play Jack Ryan...if Hunt for Red October was the only Tom Clancy movie ever made. But obviously it wasn't, and obviously he wasn't.
That wasn't my point. The point was that one cannot justifiably say that only one actor can successfully be associated with one particular role. If that was the case, we'd only have had one Doctor and one James Bond.
I'd agree except to say that Shatner did define the role and is still the one most commonly associated with it. Chris Pine is an excellent Kirk, having walked the fine line between being the character and playing William Shatner being the character.
If in the future there are to be more actors playing Kirk in the studio-produced world of Trek, and Kirk becomes like Bond, there will undoubtedly be more variance in how the character is interpreted and portrayed, with some being called better portrayals than others. Of course right now, we have a "small n" problem: there's only Shatner and Pine, and while Pine was successful, Shatner is still the benchmark. Pine was Kirk, but he didn't steal the character from Shatner.