Of course it is. Anybody who has taken Econ 101 gets to the Macroeconomic Theory section when it stops making sense because it leaves reality behind. All the parts where it talks about LOCAL economies; household budgets, small business budgets, even local governments have a reasonable number of variables, of incomes, outflows, and actors.
But on a grand scale it really depends on accurately guessing how large groups of humans will behave. That, in turn, depends on how you view people. Being one of us, I assume you view people as actors with a variety of motivations which may be guessed at. The "quality" have a very poor opinion of what they call the "herd". Most of them think God himself has appointed them by birth into the ruling class. They genuinely think we are dirty, smelly, ignorant peasants who would be unable to govern ourselves because being poor is our own fault.
This view lets them view groups in their lowest terms: base, animal motivations stemming solely from greed, lust, gluttony, etc. It is a very infantle view of people and leaves out any higher motivations like altruism, conscience, or personal liberty and responsibility found in the mature human psyche possibly because they were never taught them themselves (it's called arrested development of emotional maturity).
This is why the whole capitalist economic system that used to at least allow people a job, car, house, and family has devolved into something approaching feudalism. It is no longer capitalism, it is
1) socialism for the wealthy with subdsidies of every sort
2) austerity for the working class with no social safety nets
3) a two-tiered criminal system where money talks and poor people are assets
4) a tiny middle class used to give the workers empty dreams of improvement
It's great for the one percent, disaster for the 99%. But the wealthy hire lots of lawyers and PR firms to spin gossamer webs of words to keep us from breaking through into reality. That's why all the Mexicans are being demonized as illegal and alien and criminals. I could go on, but I think you get it. The system that worked well in the 1940s through the 1970s has been gradually changed by certain fake-conservative politicians (technically their policies are "Neo-Liberal" economics by definition, like the destructive policies of the International Monetary Fund).
If the destructive changes to our system were reversed, the damage would begin to heal, too. The mantra that government is broken and must be swept away is propaganda put out by the very people who, through their inaction and their meddling, have ground that government to a halt. There's a lot of profit to be made and even the continuance of our form of life cannot be allowed to stand in the way.