Replying mostly to bookmark this thread.
But also wondering... why doesn't the T arrange for some outer connections between its commuter rail lines? For instance, I live off the Middleborough line. Frequency is meh, but the trains never run when I want them. But why not run a bus 15 minutes up the road to Kingston to meet with those trains? This would be a short-haul route with limited stops that maybe could have some other applications and interconnect with other GATRA routes (Middleborough-Taunton, Middleborough-Wareham, the Kingston/Plymouth bus system, etc.).
These 128-to-495 and beyond places are usually under jurisdiction of a different Regional Transit Authority for the buses, so it's not a service the T can provide. And in the case of Anderson the Yellow Line coverage is so thin out there the stop was largely left to outsiders like the 128 Biz Council shuttle to fill in. And that's not a fair shake because low-margin consortiums like that can't afford to route-prime a new service for a few years until ridership catches on. 128BC had to throw in the towel years ago on Anderson even though the station ridership has been growing robustly; their finances are too year-to-year variable to commit to running a loss leader the 5-10 years it'll take to slow-cook itself into a winner.
And even in the commuter rail towns that fall into gaps between T bus coverage and RTA bus coverage, there's also the simple logistical problem of sustaining Yellow Line service that far away from the yards and crew bases. The North Shore is particularly crippled by this having to express nearly all its routes to downtown for lack of a transfer station at Lynn terminal. The bus yards don't have a big enough equipment pipeline to fill in more purely local routes with the expresses siphoning so much away.
Doing this sort of thing is wholly dependent on loosening up the funding for the RTA's to spread their wings. The RTA's do a good job today with what they have, but if the commuter rail stop isn't close to
their home base and core routes it's a struggle for them to provide the coverage. It's been flagged as a state priority for ages to provide more circulating bus service into the outer CR stations, but if the T itself is fighting for funding scraps the RTA's are fighting for crumbs-from-the-scraps. That's not going to substantially change until the money is there. But the local RTA's are fully sympatico with the need for it...so funding is the only obstacle for starting up some routes that do exactly what you suggest.
As for the indie and business consortium operators like 128BC...they need some subsidy to close the gap on year-to-year funding uncertainty so they have the cost stability to commit to running routes for the long haul. A new suburban route is rarely going to be well-patronized from Day 1 and needs time to build up momentum, build up a good word-of-mouth on its convenience, etc. I'm sure 128BC knew this and hated having to pull the plug on their Anderson shuttle so soon, but they don't have the margins to wait out slow growth and have to show immediate results. They don't have a choice. The public part of the public-private or public-nonprofit partnerships has an opportunity to help backstop the uncertainty more so these outfits don't have to worry so much about the year-to-year, month-to-month numbers on a route that's a long-term prospect.
But like with the RTA's, this can only happen only if we can bust out of this statewide holding pattern on bus transit funding. It's not just the Yellow Line that's been near-static for over a decade and had to trade 1:1 painful cuts some places to feed its growth other places. The RTA's and the indie/municipal/consortium/etc. services are treading water much the same way. And this is the result...they can't take calculated risks on useful expansion routes like radial CR transfer shuttles when their margins won't support seeing through a "5-year plan" or two's worth of slow-growth losses developing the route.
The good news is most of the state's other RTA's have now fully migrated over to Charlie Cards. So the missing link in getting these bus transfer routes some juice is getting CR Charlied. It would be a huge boost for the really well- built-out RTA's like BAT in Brockton which already has its terminal right at the downtown CR station and has already cashed in on service growth from the transfer. But it also encourages more of those calculated risks on the 495-belt stops where the feeders would need to cover more distance/less density.
Charlie's also going to be critical for converting park-and-riders into bus riders. One card needs to have the convenience of paying for parking, paying for the bus transfers, and paying for the commuter rail trip. It encourages regular park-and-riders to try the bus out of curiosity, try the bus as a backup route for bad weather/bad traffic/unavailable car, try the bus as a way to save money over escalating parking costs, or try the bus as a simple comparison to see if it's less aggravating than a drive in traffic and gives them a few more minutes vs. driving to check work e-mail on their smartphone, etc. There needs to be an 'in' that's effortless enough for them not to need to think about which way they choose to get to the CR station, not need to make a leap-of-faith commitment to a different mode without having every option available on any given day at equal convenience, and which doesn't change the way they pay for any part of their commute.
Fluidity. More people will warm to the idea of a car-free commute via bus if they can switch back and forth, fidget around day-to-day, and try it again on a whim if the first attempt didn't strike their fancy. Unified, all-mode Charlie coverage opens those doors for more service on a scale that little else can. As long as the rollout remains this incomplete omitting CR and most systemwide parking...it's a hurdle that's tough to overcome.