I think that's because of what we're talking about right now -- all of these workers heading to the big cities instead of living out in the suburbs. When the workers return to the suburbs, business will follow them, and they won't be insolvent anymore.
The suburbs around Boston are definitely not economically insolvent, and the ones in metro-west are fairly flush financially (continually building and upgrading schools and other town amenities).
Source for that claim? I hear it all the time, but never a source that actually stands up to scrutiny. (strongtowns is the most common - they are not a source)
