Maybe that's the approach for hiring...remote employees are hired with the understanding that they will earn less than equivalent in-office employees. Commute time, transportation expenses, and any other incidentals make up the difference. It's all made clear and transparent upfront.
If remaining remote limits an employee's promotability for reasons of company need, this is also made clear.
Because remote employees don't spend their own time and money on commuting to work. Those factors, along with saving on childcare, are the main drivers for desire to work remote, yes?
A company can reduce its office footprint to account for fewer in-person employees and save money. But that alone doesn't address the factors above faced by employees who commute, so those workers should be compensated.