You can thank Thurston Howell III (i.e. John Kerry) for driving up the cost of healthcare in MA. One of his last acts as Senator was to STEAL $300 million from the rest of the country by classifying a tiny 19 bed hospital on Nantucket as a "rural hospital." This stripped away Medicare funding to all of the other rural hospitals in the country and gave it to the super rich hospitals like Mass General. It's more complicated than I can explain. Google "The Nantucket Effect". Our healthcare system is completely crazy when a tiny little 19 bed hospital located on an island for the super rich can have that much of an impact on the entire healthcare system. The name of the hospital is "Nantucket Cottage Hospital" because it's literally located inside of a cottage.
Now to be fair these four states do a sizable amount of medical research for the entire world. These things cost money. People come from all over the world to go to Mass General, Brigham and Women's and Boston Children's Hospital.