Bostons a life sciences hub and basically the only game in town for serious bioengineering. Different ballgame compared to the kind of tech that gets talked about on HN usually which is basically B2B or B2C SaaS.
>>meddle+(OP)
There is plenty of biotech HQ'd in the Bay Area to seriously compete with Boston as the #1 spot: 10x Genomics, Guardant Health, Twist, Natera, CareDx, Verily, Invitae, Nevro, Berkeley Lights, Genentech, PacBio, etc.