In your exact situation? Nothing.
In order to own a hot hatch and not spend 26k over three years? Many things!
Certainly depreciation is a big one, 11k over three years is £305 a month before servicing which can be negated, but not if one of your requirements is a new car (unless you select very carefully)
You haven't accounted for the lost opportunity value if spending actual money on the car up front.
The fact you've only done 4 trackdays in 3 years but got through 3 sets of tyres (in addition to the original set) suggests you drive hard, but I'd perhaps be inclined to have separate track and road tyres.
I have no idea how on earth you've got through brakes so quickly, especially rears
Like you say, looking at your graph, fuel and depreciation are always the killers but if you get rid of the depreciation, then things like servicing become more significant too