Boston in general has always had the 128 loop containing a fair number of companies. Especially prior to the Big Dig, where congestion in and directly around the city was beyond heinous. DEC never really was in Boston, but QUITE a ways outside not just Boston, but over 10 miles outside the 128 loop as well.

Though the reality is Boston has a lot of industries. It's not just some computer tech and biotech, but the metro is still a top global education destination, still has a huge medical footprint, still has several massive financial institutions (notably Fidelity and State Street) and a decent banking footprint, as well as insurance. Boston has a lot of industry tentpoles, so it's very resilient to one industry going elsewhere, like when tech heavily shifted to the Valley long ago.

Though the MBTA's shortcomings in the past 5-7 years is starting to take its toll. I feel the T being taken over by the fed to right the ship a la DC is inevitable, and it's likely necessary for Boston and Cambridge to not significantly lose appeal. Though at least it's one of the most walkable metros (particularly Boston, Cambridge, Somerville, Brookline and Quincy) in the country.