The same state that voted against FDR in each of his presidential campaigns and where Republican candidates consistently outperformed their national results gave Barack Obama nearly 70% of the vote in 2008, two years after they elected their at-large congressman, a self-identified democratic socialist, to the US Senate. Now the same state that couldn't stomach the New Deal is introducing universal health care.
What's changed in Vermont? It's still a mostly rural state and overwhelmingly white - two things that should make it low-hanging Republican fruit. No minorities. No remotely large cities. It hasn't had an influx of Boston commuters like New Hampshire, or New York City commuters like Connecticut.
Between 1830 and 1960 grew 39%, an annual rate of 0.25%. Any children in a family beyond the 2nd had to leave the state.
Between 1960 and 2000, the rate jumped to 1.12% or 4.5 times as great. The growth was actually higher in both percentage and numeric terms in the 1960s and 1970s. The growth was focused on Burlington. Chittenden County did not surpass Rutland County to become the state's largest until 1940. By 1980 it had double the population.
From 1960 to 2010 Chittenden increased 110%. Counties in the south and east typically increased around 35%. The other high growth rate counties are all neighbors: Grand Isle 13%, Lamoille 122%, Addison 83%, and Franklin 62%. The first two benefited from a small population base (Grand Isle had 2927 left in 1960).
If you look at the state of birth reports from the census for the time before the growth spurt, it was almost all outward, to states in New England and Northeast, but also throughout the country. The only true two-way migration was to New Hampshire, and that was net towards New Hampshire.
By 2000, this had strongly reversed, with big inward flows from Massachusetts, New York, New Jersey, but also further afield, such as Maryland, Ohio, and Illinois. Even the relative flow to California had been reduced. In most of destination states, Vermont-born had declined as people born decades before began to die off.
So you have a lot of life-style migrants who didn't move so they could milk cows or collect sap. Only in those over 70 and the very young is there a Vermont-born majority.