Dr. Robert J. Barro's prescription for "How to Really Save the Economy" would save it for only 20% of the people, if that many. His standard for a good idea is: if it benefits persons with annual incomes exceeding 2 million dollars, then it's a good idea.
Where Dr. Barro's prescription breaks down is in the definition of what is an economy. If an economy is the thing that produces GDP, and if a growing GDP is a saved economy, then Dr. Barro's prescription may well grow the economy by increasing the incomes of the very wealthy. If the incomes of the wealthy increase fast enough, then the people with incomes less than $2 million can have their incomes stagnate or even decline a bit, because the GDP will still grow, and by this definition the economy will have been saved.
But if the definition of an economy is the engine of production and distribution by which all persons obtain the goods and services they need, then Dr. Barro's prescription is for "How to Really Wreck the Economy", because the poorer 80% of the people would not benefit from his prescription, and many of them would be worse off.
Dr. Barro is wrong or partially wrong on all six counts: