When WFH I would like to have a good external display for my laptop. Ditto mouse and keyboard. I would like to be comfortably warm in winter. Being cool enough in the summer is just a matter of opening windows where I live. I would like a decent desk and chair, or standing desk etc. These all cost money. At the moment some of this is born by my employer and some by me. If WFH lasts as a widely available option for several years I expect that the balance of who pays for what may change. Of the costs I listed, heating is by far the biggest deal for me - I live in an old, hard-to-keep-warm house.

But... WFH also brings savings. I used to spend significant amounts of money commuting, which is funny given how much I hated every second of it. That money stays in my pocket now. I know that the option of bringing lunch with me every day was always present, but it is the case that I eat a lot more home prepared food now my office is in the same building as my fridge, so I certainly save a bundle there.

Where I live, there is some provision in the tax code for WFH expenses, but really its so small that it might as well not exist.

What my point in all this? It is that I don't think the issue is nearly as clear cut as you make it out to be. Maybe WFH is a cost of living increase. Maybe it's a saving. Which depends on the nature of your work, the distance you used to travel, the size of cost of your living space and a host of other factors.