The only way the economy will grow at a healthy rate is by an increase in business volume.
No. the economy grows from savings and loans, not by consumption. Growth means the economy produces more goods and services than it did before. It can't do that unless it increases it's efficiency, that is: more output for the same input (labor). To increase efficiency a business must invest in new equipment, RND, etc.
If a bunch of hoarders suddenly start spending their money, business will experience a temporary spike in sales and the value of money will drop. Afterwards, the economy is no bigger than it was before and businesses will have low stock.
To sustain an increased volume a business must improve it's infrastructure. This requires capital.
This is a direct argument against your core assumption.