I really don't understand why you'd all expect a complete 13 part season every year.
As noted, the fact that Russell T. Davies and co. delivered them for four years running is a big factor.
I imagine that Moffat's team work to the dictates of BBC scheduling, which would include budgetary concerns, etc.
If there's one thing that's always been clear, it's that the BBC wants as much Doctor Who
as possible. Remember how peeved Peter Fincham was when he grasped that there was going to be a gap year in 2009 rather than a fifth series?
It's not very common for tv shows to come back every year in the same months as before. Extended breaks and revamped schedules are the norm, not the exception.
That's an overstatement. Occasional breaks and schedule revamps occur, but moving around as much as Doctor Who
has since 2009 is the exception, not the norm. Being Human
, Downton Abbey
, Life on Mars
/Ashes to Ashes
... all recent, all managing to run several years in a row with no more than a couple months' schedule shift over those years.
I don't "expect" a 13-part season every
year; I grasp the argument for an occasional gap or schedule revamp. But the plan for Doctor Who
is shifting a lot more than it used to, and I don't think it's surprising that people wonder why.