Nothing else to add except anecdata. Feels like a losing industry at the whim of the building owners. Also the upper management was filled with leeches.
It's a simple business model: commit to a long-term lease, add furniture and sublet the space in lots of small flexible short term leases. The setup also seems to be similar everywhere, with some mix of flexible desks, fixed desks and closed offices available. You mostly differentiate on location, how hip it looks, and what kind of community you can build. WeWork had efficiencies of scale on the looking hip part, but on the community building a local group can easily outcompete a multinational company.
Or maybe more like a hostel.
Though admittedly it'd be really cool if there was a co-working space that included maker-space facilities, both for the constant use of the people who are makers, and for the less-frequent use by the people who aren't.
(And so that the people who are makers would end up seated next to the people who aren't. This starts to get into "arts college" territory — where someone doing an illustration project can wander over to a friend in the woodworking department to get their illustration turned into a carving...)
Heck, while we're at it, let's throw in other facilities that would lure in people with complementary skillsets to most businesses. A teeny-tiny colo in the basement for your dev servers! Podcast recording rooms! A screening room for videos!