There are many reasons why I (and others) don’t ride intercity buses places, but do ride trains to comparable locations. Speaking for myself only, but as a single anecdote that exists in a sea of many many many people (as evidenced by the data), one of those reasons is the ability to bring a bicycle. I’ve taken the train to Rockport, Gloucester, and Manchester-by-the-Sea, and biked along the water, to beaches, to businesses, and sometimes back to Boston. I take the train to West Concord and ride the Bruce Freeman up to Lowell, patronizing businesses, then take the train back from there. I take the train to Concord, then bike back to Boston via the Reformatory Branch and Minuteman trails, patronizing local businesses and stopping by at ponds along the way. Not everybody is a cyclist who enjoys to take the train to facilitate rides in new places, but many have their reasons. And that fact is evidenced by the data referenced above.
Would I take a bus to Greenfield, Fall River or New Bedford? Absolutely not. Would I take a train to those places, then ride around that part of the state and check out the natural beauty, built environment, and businesses that exist there? You betcha. Everyone has their reasons. The bottom line is that people, for a myriad of reasons, prefer to take a Commuter/Regional train over an intercity bus and I don’t blame them one bit.