Consumption drives investment. Why on earth would you spend 10 million dollars to build a widget factory, when nobody has the money to buy widgets?
Savings fund investment. The more savings there are, the cheaper it is to find funds for investing in a project. The cheaper the capital expenditure, the easier it is to turn a profit.
Or are you talking about the paradox of thrift?
Having a lot of money searching for an investment won't do you any good when your widget factories don't have customers. Yes, borrowing money to build the factory will be cheap - but you still expect the factory to produce a return on your investment!