It’s largely filled with letters and maybe small packages (e.g., my coffee subscription). Anything larger than a large book seems to still be delivered by someone driving a van. The trikes roam the streets going door to door, the vans operate more like a courier service.

That, and also the post offices in towns are pretty close. In my area that means there's 4 of them, around 1km apart. Covering probably 20k people in the town itself + another 10k in the general area.

> Anything larger than a large book seems to still be delivered by someone driving a van.

Or a roving Packagebot(TM) ?

The e-trikes replaced old motorcycles with saddlebags. The trike rides up onto the footpath and delivers directly into the mailbox. Usually letters and catalogues. They hop from letterbox to letterbox along the road and footpath. They are coloured fluroscent yellow, same association as high visibility shirts.

Packages are done by courier in a van or truck. Grocery deliveries are done by supermarket branded refrigerator trucks. Local fast food is done by the ubereats/menulog crowd.

A local automotive store will drop off parts by an employee in his car.

It sounds like americans get more packages delivered in one go, by the us postal office trucks?

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.

In turn USPS uses FedEx for international and (maybe not anymore) for overnight deliveries to certain destinations.

Seems like a sensible division of labor. So what's the catch ?