I can tell you some of the resistance is just that it is a pay cut and time management difficulty to resume the commute to the office and back.
People had been able to offset cost savings against inflation, but having yo pay gas and tolls or fares again every day and losing hours of personal time to tedious travel, while having to potentially adjust family schedules considerably is going to be considered a major drawback.
I'm sure many people considered work from home in lieu of seeking out pay increases to offset personal expenses a fair trade, but if that is revoked, a lot of people will start seeking out jobs where they can still do that, or will start seeking out more compensation for their time against inflation.
Employers aren't going to like that they can't just turn off the WFH switch in a low unemployment rate environment without consequences.