The problem is that it likely snowballs one way or another if you allow full flexibility.
If more people initially chose to work at the office, then the minority WFH people will inevitably be at a disadvantage and they would feel potentially left out of a lot of developments that take place in the office. Then they may end up forcing themselves to go to the office from time to time or move to a different company where more people WFH.
Or if more people initially choose to WFH, then the value of going to office gets diminished and then one may start WFH more and more since not a lot of people go to the office in the first place, then the places becomes pretty much full remote and the company may just close it down to save real estate cost. Then you either are forced to embrace WFH or you have to find a different job with a different culture.
People who have experienced multiple varations of WFH know that this is true. You can have all colocated or remote-first, but adding flexibility for any other varations means someone is a second-class employee and more work for them. It's not imposssible; plenty of companies are blended, but it's not ideal.
If more people initially chose to work at the office, then the minority WFH people will inevitably be at a disadvantage and they would feel potentially left out of a lot of developments that take place in the office. Then they may end up forcing themselves to go to the office from time to time or move to a different company where more people WFH.
Or if more people initially choose to WFH, then the value of going to office gets diminished and then one may start WFH more and more since not a lot of people go to the office in the first place, then the places becomes pretty much full remote and the company may just close it down to save real estate cost. Then you either are forced to embrace WFH or you have to find a different job with a different culture.