How is industry productivity not relevant to the point being made? It’s quite possible for there to be a direct correlation between work productivity and industry productivity.
You are also discounting many other benefits of remote work. While yes someone may be doing laundry when they should be filling out expense reports, they are also not spending time on a lengthy commute. As a result they are also spending less time at the gas station and for car maintenance bills. I’ll admit I do personal chores on the company’s dime, but the time and resources I save by working remote make up for it at the very least.