Boston has had at least one $1B+ tech IPO (not including bio) every year for the last decade. There have been as many High nine-figure, billion-plus acquisitions in the same period.
Boston doesn't get much in the way of national PR, but it's arguably the 2nd best city in tech, measured by liquidity over the last decade, in the country.
And not just in boring security/B2B areas. Wayfair is a top 10 ecommerce player. CarGurus has thoroughly beat TrueCar. DraftKings created its category.