As compelling as some of the evidence regarding pre-Hartnell incarnations of The Doctor is, there are still glaring problems with the theory. Perhaps the biggest problem is that the show itself basically confirmed the exact number of lives The Doctor had, due to his original regeneration limit. When Matt Smith’s Eleventh Doctor is at the end of his run, he faces legit mortality due to using all 12 possible regenerations.
In the end, it requires the Time Lords to grant the Doctor a whole new round of regenerations to keep him alive. In the process, it’s pretty obvious that this is the first time The Doctor has reached the end of a cycle. Counting the number of regenerations the character has undergone up to this point in the series, the calculations firmly indicate that Hartnell’s First Doctor is the first incarnation of the cycle. If the concept of Timeless Child is true, it should somehow reconcile with this plot point.
It would seem that while there are some issues with this particular fan theory, there is also plenty of supporting evidence. Fans may never get a definitive answer to the debate, but it’s certainly fun to speculate and consider what The Doctor’s life was like before “Doctor Who” debuted.