as a board member or shareholder I think I would ask the inverse question.

Okay, we have two years of data. PROVE to me that you need to spend $Xm per year on office space for this company to work. Prove to me that you have to pay top of market SV salaries

I think the time is now to reframe what needs to be proven...its a business not a social experiment. Coming in costs more money, prove to me its money worth spending on a case by case basis. If you don't run a handson manufacturing line what evidence supports paying for a building where everyone has a space? We've already ditched offices for cubicles and cubicles for open plan offices just to save space (i.e., cost). At this point the burden of proof isn't on 'work from home is okay' just from a financial perspective.