Earlier quoted context omitted.
It’s also awful timing. After what, 18 months of productive WFH now they want to cut salary?
If Google felt that WFH had no negative effect on productivity, they could go the route of Twitter and others. The C-level clearly disagrees that this arrangement is ideal for the company, and are disincentivizing it with pay cuts.
I'm not saying this is definitely the case in google's situation, just... "effect on productivity" is hard to measure, and may have more than one measurement.