As friends in the industry explained to me, the competitive tender is something the bbc is required to do by law--since they no longer produce anything, they have to. (Their production arm is BBC Studios iirc).
So it's mostly a case of changing showrunners, which isn't wholly surprising.
▶️ "The BBC will put Doctor Who out to competitive tender this year."
▶️ "The BBC, Russell T Davies and Bad Wolf have collectively decided not to go ahead with the previously announced Doctor Who Christmas episode."
▶️ "We are choosing to push forward to invest in the long-term future of the show."
