I think what will kill off this current iteration of the show is what has been growing for some time anyway. And that is viewer apathy.
Whatever enthusiasm was there on the part of the viewership during - particularly - the Tennant era, I would contend is gone.
I don't think viewers were quite as enthusiastic for Matt Smith, in comparison, and even less so for Capaldi. even though I think he was a brilliant Doctor, struggling to establish himself despite his showrunner.
Now the enthusiasm for Jodie Whittaker is the most compromised of all, with only just over half the audience actually seemingly being interested in seeing a female Doctor.
That is devastating.
I would also argue that those who voted with enthusiasm for the idea of a female Doctor may not necessarily all be sticking around to watch her adventures. A certain portion of them may just approve of the idea. This doesn't mean they are really fans or want to watch the show particularly.
I think the BBC knew they were taking a gamble in changing genders, but were desperate enough to do something to get the show noticed again in the face of falling ratings etc. Chibnall went to them with the idea of a female Doctor and was surprised at their enthusiastic agreement, expecting them to struggle with the idea.
Now that the idea has been met with a certain division, they will be on edge, waiting to see what the proof of the pudding is.
If the ratings drop, you can bet some kind of dramatic decision will be made at the top of the chain, while putting on a brave public face.
My prediction is that Jodie's second year will happen, but that it will be a series of specials.
Then either a finale of some kind.
Or nothing.
A BBC statement I am predicting will go something along the lines of......
While Jodie's tenure as the Doctor has been a real shot in the arm for the show and fandom has embraced her as one of the best Doctor's yet, the BBC feels that it is time for the show to have another one of it's periodic rests, which is always good for the show in the long run. Have no fear though, the Doctor will return to battle the perils of the Universe - and sooner rather than later.
This is really how I see it playing out.
All they care about is ratings and merchandise. And if the show is returning neither, then sacrifices will be made.
Diplomatically made, of course. But still made.
Even if what is on screen is actually brilliant, artistically.
I am willing to be proved wrong of course. Time will tell.
So we will just have to wait and see now.