It's very difficult to be "sitting on piles of money" in the way you imply unless you've literally perched yourself atop a chair constructed from stacks of US dollar bills.
When a millionaire earns an extra million dollars, he or she puts it somewhere - into stocks, or bonds, or other investments, and sometimes, rarely, keeps it in a bank account for years on end where it sits and earns no interest. With the exception of the bank account, all of these are capital re-investments that stimulate the economy in some way.
When a millionaire earns an extra million dollars, he or she puts it somewhere - into stocks, or bonds, or other investments, and sometimes, rarely, keeps it in a bank account for years on end where it sits and earns no interest. With the exception of the bank account, all of these are capital re-investments that stimulate the economy in some way.