The problem with this model is that when demand for real estate falls (e.g. because of economic cycles, trends/tastes, etc.) the revenues will evaporate and the costs will remain.
If WeWork can't pay the lease on 29,000 square feet of office space, WeWork has a problem. If they can't pay the lease on 2.9 million square feet of office space, the owners have a problem.
One fairly big serviced offices company pulled the "separate entities" trick in one of the previous recessions, and some of the major landlords in that country still to this day, more than a decade later, refuse to do business with them.