Government does not create wealth, true. But the people government taxes create wealth, so the point is moot.
The point is not moot. How much the government taxes its subjects, or regulates its behaviour, determines how much a bottleneck that government becomes to that productivity. Tax rates affect productivity. Tax rates affect the willingness of entrepreneurs to risk their money on new ideas, or invest in growing productivity.
Also, remember that if you have time to go adventuring, you're probably not attending to anything that would be worth higher pay. You believe the rate before mismanagement is higher than a nickle per subject. But if all your subjects are getting is a vicount who out adventuring, perhaps that is all the job is worth.
("Your yachts are entailed and your father's will require you to keep them manned at all times. Yes, everything else you own except for what is on your equipment sheet is entailed too. Yes, even you diamond cufflinks, your golf clubs, your hunting rifles, and your fishing tackle), it might strain my willing suspension of disbelief just a tad.
Just a bit? This is a valid point. But don't you have the same problem if you inherited 3 yatchs from the previous vicount?
The point I've been belaboring is that I don't think that 1.5 centicred per subject is the upper limit for what an overlord can extract from his country without causing detrimental economic consequences, insurrection, plague, bad weather, and loose morals.
First off, its by land area and trade code, not necessarily population. Slath has a population of 300 on the whole planet, and the fief there generates the same paycheck per hex as the barony on Lemish, which has 1 million people on that planet.
Second, I am not so sure. Are you subjects getting their 1.5 centicred's worth of effort on your part? Are you doing something that is creating or helping create an equivalent amount of wealth, or increase in the GDP?
Third, it seems possible to change the trade codes of your specific vicountery hexes, and thereby boosting your paycheck. The baroness has been talking about adding some kind of Tyranasaurus (or equivalent,) ranch, to our lands on Lemish, both as a tourist attraction, as well as a source of meat and leather for sale and export.
Incidentally, I'm not really all that concerned about the game effects. I'm fine with player characters that don't have the disposable income of rulers of average countries. What annoys me is the worldbuilding ramifications of rulers of average countries that don't have the disposable income of rulers of average countries.
You are worried that because your hexes are not generating the level of income you require, you will be unable to invest that wealth in improving the infrastructure of your lands? I think there is a way work out the actual government budget, consistent with the law and government levels, but may require a level of detail not available in the rules yet.
What would you consider an alternative rules to compute your vicountery paycheck?