In many ways, the map is a pretty good look at where folks with big incomes or valuable homes live who have access to CR: Wellesley, Winchester, Medfield, Cohasset and those that just have fancy houses (Dover, Marblehead, Lynnfield)
And confirms the intertwined concepts of 40B housing (every community should accept some residents with slighly-lower than the local median) and TOD.
CR TOD is perhaps the "mildest" type--these are fancy people with "downtown" jobs, or they're going to be downsizing or consulting kind of households.
A condo or townhome in Wellesley, Winchester, Medfield or Cohasset is still going to be plenty expensive and filled with people who are plenty fancy (by statewide standards), and yet are willing to live in a slightly denser neighborhood that's walkable to CR (or just a good place to "downsize" to). Either way, it should be every community's job to host its own community-appropriate share of such housing on transit.