That's possible, but you could make the argument about any perk. Having free lunches, or paying high salaries puts companies at a disadvantage relative to competitors, all else equal. But if you free people to focus on what matters, and attract more competitive talent, it might balance out. Especially in light of attracting more competitive talent, it remains to be seen how it will balance out.
Good point. Also consider this scenario:
Direct competitors choose different WFH policies.
Company A: exclusively in-office.
Company B: exclusively WFH.
Company B can allocate all the savings from office space and infrastructure towards increased employee compensation (or whatever else they choose to spend on).
Will the cost of office space prove valuable for the benefit of the in-person bonus performance?
I think that a "Company C" that kept all their office space and still allowed employees to exclusively WFH would be making a mistake.