Yes. Congress required the USPS to be profitable, and then required it to up-front fund its pensions, and then capped the rate they can charge for first-class mail. This created incentives for them to deliver more parcels. One service they offer is "last-mile" service for private parcel carriers; so e.g. FedEx will get it to your city and USPS will deliver to your house. A significant fraction of packages ordered through amazon will arrive via a postal carrier where I am.