One of the key benefits of WFH is that people can leave the city where rent is expensive and find a bigger flat for cheaper outside the city limits. In my opinion the ability to have more time to spend with my family and friends outweighs any benefits of having a chef or gym at the office. On another note cooking is one of the most valuable life skills I learned to late, I recommend taking it up, not only does it help with living healthy but it's also a good way to relax and take your mind off things or spend time with your significant other :)
They are benefiting from this just as much as you are. Remind your employer that he's also saving money by not having to pay for an expensive office space in the city center and all the things that go with it like hiring cleaning services or building staff. Any equipment you use to work on should be either reimbursed by him or factored into your salary as well (monitor, laptop, internet connection, office chair, desk, etc). There are a lot of bargaining chips, just depends on how you present them.
I guess perspective matters, in my opinion an average engineer working at Facebook should be able to afford his own house in a nice neighborhood and be able to provide for his/her family so that they live well. If that's not the case then maybe engineers ought to start forming unions or demand profit sharing from companies.
The more employers willing to hire remote workers, the less this argument works.
Still, I already make 1/2 as much as I could make living in Boston, living 90 miles north of it. That is "local market" salary though for a job that is ostensibly on-site (partial remote / now fully remote due to COVID).
