One can play the "then and now" game with Downtown Crossing nearly infinitely--the BLC's Central Business District archive on Flickr has at least 300+ shots from the 1950s-70s. Combat Zone, Upper Washington, Gov't Ctr/Scollay Sq, Franklin St, Chauncy--voluminous.
Also, this conversation about what's "really" happening in DTC right now seems way too "either/or," black-and-white and not nearly nuanced enough.
It's obvious that the district is revitalizing in the sense that street-level restaurant/retail vacancies are re-tenanting to levels not seen since pre-Combat Zone heyday. That's a reversion to old. At the same time, DTC is gentrifying due to 1,000s of high-priced condos and apartments coming online since the 1990s and especially post-2009. That's a new positive. At the same time, the homelessness situation is clearly intensifying. That's a new negative. Also, the T is falling apart and that phenomenon is particularly felt in the subway convergence zone that is DTC. One could go on...
All these trends are coalescing and interlocking and interplaying with other trends. That's life. So why does everyone always seem to succumb to binary "it's bad"/"it's good" mentalities?