Government spending, not private enterprise, is the engine that keeps the show running.
But government spending is not the whole show. It just allows the show to exist.
Take away the government spending and the economy collapses.
That was the argument several economists made when WWII came to an end and the government reduced its spending by more than half, but the economy didn't collapse. The same thing would happen now and it would even get better without the government spending.
War is the ultimate consumption driven economy. When the war is over the consumption stops, there is no reason to continue the high government spending. I have my doubts that you can provide any examples of economists who wanted to continue the wartime government spending levels. Virtually all of the economists that I know were concerned not with keeping government spending high, but with the opposite problem of inflation because of the pent up consumer demand from the war and the inability of producers to switch over from producing war goods to producing consumer goods. Fortunately the Institutionists and Keynesians that had run the wartime economy did pretty much the right things, they provided funds to convert the industrial base back to production of consumer goods, they kept taxes high to prevent inflation, they provided money to help rebuild the destruction of the war, think the Marshall Plan and they passed the GI bill to reduce the glut of labor from the returning servicemen and to encourage the housing market, which didn't require much time and investment to get up and running. .
Government spending is about 25% of the economy. It hasn't changed dramatically in years. What does change is the amount of money that government spending creates and puts into the economy.
If taxes cover the government spending then the government isn't creating and putting any money into the economy. If the government is running a deficit it is creating money and spending it into the economy. If the government is running a surplus it is taking money out of the economy.
It is maybe helpful if you think of taxes as destroying money and government spending as creating money. The only reason that the government has to keep the balance between money creation, spending, and money destruction, taxes, in some balance is to avoid inflation, too much money, and deflation, too little money.
What most people don't appreciate is that the balance of trade has to be included in the equilibrium between spending and taxation. If the country is running a trade deficit, as we are now, then the amount of the deficit is money that is leaving our economy, money that has to be replaced in our economy. There is only two places that it can come from, either reduced private savings or increased government deficit spending.