Professor Zoom wrote:
What do you mean, "one less." That implies that the show won't go on forever and forever, so long as it remains popular.
Are you saying they would STOP the show after the 12th or 13th Doctor?
Quite right. The 12-regeneration limit was itself a retcon that wasn't introduced until about halfway through the original run. And the show wasn't even consistent about whether Hartnell's Doctor was the first. "The Three Doctors" had a character refer to him as "the earliest Doctor," but the later "The Brain of Morbius" had a scene showing what purported to be the faces of as many as eight pre-Hartnell incarnations. (Fans have rationalized them as being Morbius's earlier incarnations, but that wasn't the intent of the script.) But by "The Five Doctors," it was again assumed that Hartnell's Doctor was "the original, you might say."
In short, Doctor Who
has never let continuity get in the way of the stories it wanted to tell. Either they'll concoct an explanation for how the Doctor can have more than 13 lives, or they'll just ignore the regeneration limit altogether. In "Death of the Doctor" on The Sarah Jane Adventures
, Russell T. Davies had the Eleventh Doctor say he could regenerate 507 times, which could be taken as a joke, but was basically RTD suggesting that there was no reason to cling to the 13-life rule. Of course, fans are so attached to that particular bit of trivia, even though it was rarely mentioned, that I'm sure the show will address it in some way.