About the taxation calculations, you’d said average yearly incomes to be about 3-5 dragons for the average person. Could you tell me how you arrived at that figure? Given that a proper warhorse in times of war costs approximately 1 dragon (Jaime’s estimate in ASOS), annual income of 3-5 dragons seems rather overly generous.

I took it from here:

The stableman gave him three gold pieces and the rest in silver. Dunk bit one of the gold coins and smiled. He had never tasted gold before, nor handled it…the heft of all that coin in his pouch made him feel queer; almost giddy on one hand, and anxious on the other. The old man had never trusted him with more than a coin or two at a time. He could live a year on this much money. (Hedge Knight)

So according to Dunk, 750 silver or three and a half gold (which he got for selling one horse, btw) is a good year’s income for a smallfolk like himself. 

And since we see that a heavy meal of “lamb…as good as any he had ever eaten, and the duck was even better, cooked with cherries and lemons and not near as greasy as most. The innkeep brought buttered pease as well, and oaten bread still hot from her oven,” plus four tankards of ale works out to a handful of copper (when a loaf of bread costs three coppers normally) less than a silver, we can begin to get a sense of what kind of standard of living one could have one two silvers a day. 

The reason why I took five gold as the high end is that the Hedge Knight happened a hundred years prior to the present of ASOIAF, and you would have gotten some inflation over that period.

But let’s take Jaime’s example: a fine warhorse works out to anywhere between a third and a fifth of a yearly income for a smallfolk – taking the average income in the U.S today, that horse is worth about $9,000-15,000 – which is pretty high, considering that the “American Association of Equine Practitioners estimates the minimum annual cost of owning a healthy horse — not including stabling costs — to be at least $2,500.”