CUTTING THE $4 TRILLION ANNUAL FEDERAL BUDGET BY 25% WOULD TAKE IT BACK TO WHERE IT WAS ONLY NINE YEARS AGO?

​And a cut of 25% would equate to $3,125 for every man, woman and child in the United States?  That’s what one commentator says:

​A $4 trillion annual budget is about $12,500 for every man, woman, and child in the United States. If the budget could be cut by, say, $1 trillion — taking it back to the 2008 level — how much good could that money do in the hands of families and businesses? How many jobs could be created? How many families could afford a new car, a better school, a down payment on a home?

From a June 9, 2017, post by David Boaz, titled What Do the Subsidy Recipients Think About Cutting Subsidies, at the Cato at Liberty blog.
How is it that cutting the federal budget back to where it was only nine years ago would be the unmitigated disaster that it is portrayed to be?