Whatever his merits, I doubt many people would care that much if Craig didn't come back. He isn't 'James Bond' in the public's eye. Not in the way Connery and Moore were, anyway.
Who is this mythic "public" folk bandy about when making blanket assumptions about how popular something is. There is no such thing as the general public and I doubt very much if people have questioned every cinemagoer in the last five years what they think. The box office does the only talking here that is remotely useful.
I have to concede that I haven't taken a worldwide census on the subject lately. However, I suspect that most people on the planet think of either the actor Sean Connery or the actor Roger Moore when they hear the name "James Bond". My personal opinion is that the vast majority of people on this planet would not suffer from sleepless nights if the character of James Bond was not played by the Cheshire-born actor Daniel Craig in the next film. I have no statistical data to support this opinion, however, and am fully prepared to accept that the vast majority of people on the planet may indeed endure sleepless nights if such an unlikely event were to occur.
People may well think of Connery or Moore when the name James Bond is mentioned, as they have been around in the public domain the longest. Those youngsters who viewed Bond in the 1990s will think first of Brosnan. Newcomers to Bond in the 2000s will associate Bond with Craig. Plus, many have good memories of Dalton's tenure - I certainly do - and for a number who came to Bond in 1970, such as me, the man of the moment was Lazenby.
But I would guess (I'll put it no higher than a guess!) that people on the whole don't reach for an insomnia cure because one particular actor may or may not appear in the next Bond film, any more than they bemoan the fact that their favourite "arguably most popular" actor is no longer Bond, or that someone else is, and has supposedly put the series in jeopardy (which seems to be the basis of this thread, and can be easily disproved by reference to the box office returns, critical reaction, and, at this time, the MGM situation.)
The Bond role is bigger than the actors concerned. Punters go to see a James Bond film, not a Connery/Lazenby/Moore/Dalton/Brosnan/Craig star vehicle. If I'm wrong, how can one explain the series longevity? The star of a typical Hollywood hit is the actor at the top of the film poster. The star of a Bond movie is James Bond.