Connecting buses (most but not all exclusively for train riders) are what makes Cal-Amtrak relevant. They allow purchase of a "train" ticket between many places that aren't on the rail line, or at times when trains don't run. Amtrak "Thruway" buses aren't a California-only proposition, either; they are used all over the country in corridors where alternatives other than driving are difficult or impossible to find. So "get on the bus, Gus" can easily be part of riding a train.

Greyhound is still in business, along with its Bolt subsidiary, and doing reasonably well. Megabus exists, too. Both, obviously, have dropped most service other than the main lines that make money - there's no ICC or public utilities commission that has power, any more, to require loss-making service or impose actual common-carrier responsibilities. Sometimes, a rural Greyhound run may be subsidized by a local government to provide minimal service; it seems more common, though, for a local government to set up its own rural transit service. In a few cases (such as San Jose-Santa Cruz) the "Amtrak bus" actually is the transit bus accepting an Amtrak ticket.

Bus fares are still a little lower than Amtrak fares for competitive trips. That, and on some routes more departure times than the train can provide, are the main benefits of the bus. The bus is usually not faster than even common Amtrak trains. If there's a train alternative, even if it's used like a bus (San Joaquins), it's usually more comfortable than any bus.