I actually rented separate space for that. So I pay for 50 m2 of private office space where I have two rooms, kitchen, bathroom, a desk with a comfortable chair, a bed, some simple gym equipment and other amenities. And in spite of paying for this every month, I would never ever come to the office where I could use some of these things (an old office chair) for free. It feels like some dark era has ended, at least for a certain type of employees.
I had a co-worker who rented a small office, close to his home. Because he lives far away from any larger towns he was able to rent an office for $200 per month, but he shares the space with his partner who also works from "home", so it's effectively $100 per person. Our employer paid for the office space, but not for the cleaning, because it was still cheaper than paying for him being at the office every day (we where short on space).
Depending on where you live, and your living situation renting a small office can be really cheap. In my local area I've seen private office rent for as little as $120 per month, but around $200 is more realistic.
Yes. Every type of employment puts undocumented costs at the employees.
But not all types of employment puts the same amount of costs. Those vary widely. And the possibility for the employee to optimize them also varies.
And all the comments up to now are still ignoring the elephant on the room and didn't touch the opportunity cost of having your entire family work on the same geographic area, and the insane housing costs on the few small areas where a family can do that.
I'm very happy for him, really! Also, I enjoy it when I pop into the office one a few weeks, it's an enjoyable experience - and part of this joy comes from the fact that I know I'm not forced to come there every way but it's my own choice.
I spent most of the pandemic working from my dining room table. Now when I work from home it is from table in the basement. Neither is particularly in anybody's way.
So that's your personal experience, but you can imagine that this might be different for different people.
The point is that previously you had a choice over the amount of space you need at home, there are requirements for WFH. i.e. You need a place where you can work effectively.