For at least some who want to live in a city and are WFH full-time, it will make more sense to rent a co-working space than to move to a bigger apartment with a dedicated office.

And I think there's a currently underserved niche of single/DINK people who would enjoy the freedom of remote work but don't want to spend the working day socially isolated.

I'm not sure how underserved it is. I suspect that a lot of people just don't want to pay for a co-working space out of their own pockets and would normally content themselves with going to coffeeshops, etc. to get out of their apartments.

Added: And people can make do with situations for a limited length of time whether working from their kitchen table or suffering through a 90 minute commute that aren't necessarily sustainable long-term.

Maybe there is some in between? Personally, I like the idea of the cafe as a local work space I can walk to from my apartment, but would love it if there was some guarantee of having a desk and niceties like a monitor or print/copy/fax/ship. I would pay some membership dues for a coop space like this.

people dont want to pay 2 rents for no reason though, unless the rents are very cheap, so they won't be able to price these things high anymore. probably

Rents for this would be work from home space would have to be modest. Gym membership rates would probably most fair. The equinox priced areas will be painted smoke grey with dark wood desks, and be stocked with instacup coffee. The snap fitness type place will be like your high school library, and will be good enough for me if I have a few square feet of desk and a monitor.