I'm not sure that calculus is correct as Google bought all 3 of the buildings they have in Chelsea in NYC. The most famous of which is the old Port Authority which is 3 million square feet and takes up an entire city block.[1][2][3] I'm not sure they're saving anything with empty office space. They kicked all previous non-Google tenants years ago. Further there is now a current glut of NYC office space with a vacancy rate of almost 19%.[4]

[1]https://www.wired.com/2010/12/google-nyc/

[2] https://techcrunch.com/2018/03/20/google-bought-manhattans-c...

[3] https://therealdeal.com/2019/05/22/google-scoops-up-another-...

[4] https://www.nytimes.com/2021/07/01/nyregion/manhattan-vacant...