I consulted a Fuller fan who maintains a FAQ and other links, I will contact another person.
FYI - Here is a link to my personal story about Fuller. I should write more. [LINK]
My email address is john at timehaven.us
Critical Path
Thanks to CJ Fernley http://www.CJFearnley.com for locating this On page 264, of some edition:
At present all the great new city
office buildings have fancy plumbing (with which only the typewriters
sleep) while a majority of city people sleep in inferior quarters with
poor plumbing. The moment we start giving everyone those handsome life
fellowships, we will find almost all the great new business buildings in
the cities being depopulated to such an extent that we shall, in quick
order, be able to turn those buildings into great apartment houses and
hotels to accommodate the free-will residential convergences of humanity
in central cities. Although such skyscrapers are far less efficient
than the ultimate
city buildings, they will provide a satisfying
step forward in accommodating humanity's successively occurring desires
and needs to deploy into wilderness country or archeological research
country or sports country or to converge to meet with other humans for
conferences or other collateral developments of which there will be an
ever-multiplying, exciting availability.
Operating Manual for Spaceship Earth
In chapter 8, 'the regenerative landscape':
We soon will begin to generate wealth so rapidly that we can do very great things. I would like you to think what this may do realistically for living without spoiling the landscape, or the antiquities or the trails of humanity throughout the ages, or despoiling the integrity of romance, vision, and harmonic creativity. All the great office buildings will be emptied of earned living workers, and the automated office-processing of information will be centralized in the basements of a few buildings. This will permit all the modernly mechanized office buildings to be used as dwelling facilities.
Playboy interview (February 1972)
a candid conversation with the visionary architect/inventor/philosopher
You can read his interview via the BFI website. HOWEVER, the notion of converting office towers or shopping malls does not appear in this interview. [PDF]