No - in a low rate environment the riskless return on money i.e. lending it to the US Government generates very little interest income so investing in any private sector enterprises - companies that are building homes, factories or new products and services is going to generate a high enough rate of return to make the risk worthwhile. This investment makes the economy grow where leaving the money with the Government doesn't.

The Fed has kept rates low for several years to encourage banks to leand money to business and keep the economy growing.