I have never seen any reasonable examples of what could be "quantified" here though. To be clear, leaders at big tech companies are not so worried about "number of tickets closed in office vs. remote" or some such related easily quantifiable metric. And the jobs that are easily quantifiable are the ones that leaders are least worried about doing remotely (both up and down the spectrum, from call center workers who can be measured on number of calls, to diagnostic radiologists who can be measured in RVUs).
Corporate leaders, especially in tech, are largely worried about a slow deterioration/decline in innovation, general employee dedication (i.e. employees feeling less connected to their job), and overall quality. Those things are extremely difficult if not impossible to measure, especially since they can take years to pan out. I'm certainly open to hearing counterpoints, but I haven't heard any yet that sound believable to me.