The reasons you've cited ought to be reasons for an employer to require office attendance. If employees are less efficient when working from home, then they shouldn't be offered full-time wfh.

As I understand it, the rationale behind offering pay-cuts to full time wfh employees is that the pay cut is relative to the employee's lower cost of living. The employer sees an opportunity to avoid including the cost-of-living salary-uplift that is required to attract people to San Francisco etc.