>And it's even incorrect as a practical matter in the modern USA, where government revenue as a share of GDP has been going steadily downward for like 70 years

>And it's even incorrect as a practical matter in the modern USA, where government revenue as a share of GDP has been going steadily downward for like 70 years now Because government spending increased explosively before those 70 years. First, the government essentially took a loan from future generations through social security and second, there was an enormous war that the government mobilized the economy to fight. You would expect spending to go back down after both of them.