Regional reversals in Massachusetts since the 70's

[soniquemd21921]

Three extreme regional shifts have happened since the early/mid 70's:

1. The small towns of Franklin and Hampshire County have, in a generation, transformed from being the most Republican towns in the entire state to being both heavily Democratic and liberal - voting for Martha Coakley by large margins.

2. The reversal of southern Worcester County from overwhelmingly Democratic to a highly competitive and Republican-leaning area that Bush, McCain and Romney got more than 40% of the vote in and Scott Brown won.

3. Dukes County (Martha's Vineyard), which used to be as Republican as Cape Cod, but in the last 30-40 years has become a very Democratic county; it's gone from the state's second-most Republican county to third-most Democratic.

What's happened in these three areas over the past 40 years? I have a feeling that #1 is the same trend that's seen the almost complete collapse of the GOP in rural/small-town Vermont and New  Hampshire, while #2 might be a combination of a Catholic vote shift + exurbanites, and #3 seems to be a trend of tourists moving in.