The actual quote is "In fact, in places where we’ve been able to reopen Google offices in a voluntary capacity, we’ve seen nearly 60% of Googlers choosing to come back to the office." That doesn't sound like surveys; I think the 60% of people came to the office once or twice interpretation is more likely.

(Also possible that the offices that were opened were more heavy on hardware / "lab" roles, so while maybe it was officially "voluntary", those people effectively had to choose between coming back to the office or doing fake / busy work at home.)

I think the thing you may be missing is that almost all of those offices are in Europe, Asia, or Oceania. I know my coworkers (I work at Google) in those locations are largely back in the office some, and excited by that.

Having worked from the Zurich office myself previously, most people are within walking/biking/a 5 minute train ride to the office, so commute concerns that we have in the US aren't relevant.

Similarly, most people in those locations live in apartments or condos and so may not have a space to make a home office. Returning to the office to make use of the (superior) workspace in the office. I can say that for example on my team, around half of my coworkers (whose offices are open) are consistently in the office.