Here's new evidence office space will decline.
In a NYT article last week with the great headline "Commercial and Residential Move in Together,"
real estate developer Helena Durst said "It's getting harder and harder to do office construction.
Housing is so much more valuable now, even in Midtown (NYC), it's taking over."
With people living downtown, and apparently forcing out lower return/profitable office space, office space will decline. Few people will live downtown and then commute to an office in the suburbs.
It's clear, and the NYT writer Matt A.V. Chaban confirms it, that mixed-use development is THE zoning of the 21st century.
He writes, "More developers are combining commercial and residential space....an increasing common practice throughout....the world."