Funny how GRRM never answered tax policy in his own books. We don't know how Tywin Lannister's tax policy differed from Robert Baratheon's, and how the Mad King's tax policy differed from theirs. Apparently the Mad King left a full treasury when he died, but that just makes him losing look all the more foolish, since a full treasury means he could've easily spent money to add a large army of mercenaries to his son Rhaegar's army, so the boy could've crushed Robert's Rebellion in the Trident. Or have the large army of mercenaries guard the capital when Rhaegar dies, so someone like Tywin couldn't take advantage of the chaos. It also makes no sense that a complete nutcase like the Mad King is far less spendthrift about money than someone like Robert, who had the wise Jon Arryn as his prime minister, handling most government affairs while Robert hunted and whored his youth away.
Also, given how the people of Gondor are content, it's more than likely that a growing number of their population are rich or well-to-do third estate people. They obviously aren't poor. We also never saw a defined aristocracy outside of the Steward of Gondor and Isildur's line, so it's obviously not the same as the Middle Ages where you had a clearly-defined noble class. You mostly had soldiers and citizens, which makes it more like Emperor Basil II's Byzantium, which is appropriate, given that Minas Tirith was modeled after Constantinople.
We also saw from the Shire, which is protected by Gondor, where you have a lot of hobbit farmers owning land and living well. Tolkien gave more life and detail to his world as opposed to GRRM who just had "LOL Dark Ages dystopia" for most of Westeros outside of Dorne, which was his fantasy Umayyad Spain archetype that has gays and lesbians fully tolerated, which was unrealistic as hell.
Tolkien's lore also went into detail on what happened with the Orcs; they just lived underground like mole-men, free from Sauron's influence. They still had a natural aversion to light, so they formed their own societies underground, not bothering anyone, and the Gondorians and Elves were content to let them be; kind of like how Ulysses S. Grant allowed Robert E. Lee to take the Confederate army home unscathed after the American Civil War ended.
Also, Tolkien was going to write a sequel story for LOTR, but he never finished it, he just got tired, and he canceled it and said that Aragorn ruled well and justly. Which was the wiser decision, since GRRM drowning his books in details just ends with him writing three good novels, two novels that are bloated as fuck, and two novels that aren't coming anytime soon.