Massachusetts might be partly due to economics. It has a combination of low gas prices and high electric prices that makes it the least favorable state for EVs.
Using statewide average gas and electricity prices as of a couple weeks ago or so (whenever I last grabbed the data) a pure ICE RAV4 has a lower energy cost per mile than a Tesla Model Y (the trim with the highest MPGs) there on the highway. The Tesla still wins in the city.
Change that Toyota to a RAV4 Hybrid (non-plug in) and then the RAV4 wins both highway and city.
Go for a Prius and then there are 8 states where the Prius beats the Tesla on both city and highway (Connecticut, Hawaii, Maine, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont). There are two where the Prius wins highway but not city: California and New Jersey.
The states most favorable to EVs are Washington, Idaho, North Dakota, Utah, Nebraska, Oregon, Wyoming, Montana, Nevada, Missouri, South Dakota, Iowa, Arkansas, Louisiana, and Oklahoma.
In those states gas prices would have to fall about 60% (Washington) to 35% (Oklahoma) for the Prius to win.
It's interesting that most of the states where energy prices most favor EVs are red states.
Note: the above was using residential electricity prices. For people that can't charge at home the Prius will win a lot more. Around here the best commercial charging is about twice what residential charging costs. If that holds elsewhere then I think only about 8 states would have the Tesla come out ahead of the Prius.