One of my clients has a space in one of WeWork's San Francisco locations. Every time I've visited, I have been struck by how many of the spaces seem underutilized (i.e. companies have more space than they're using). For example, I see companies that have private offices with x desks but I only see x/2 being used at any given time.
Other private offices appear to be entirely unutilized (i.e. they're occupied but I never see anybody in them). The latter seems to be more common with large companies that have "real" offices elsewhere and don't really need space at WeWork.
My wife's workplace currently has a WeWork office, as well as a manufacturing facility outside of the city. They typically alternate days, switching between being at the office (which has the 'prestigious' New York City address and most of the paperwork), and the warehouse out on Long Island.
They used to have a bigger office, and my wife would typically be the only one using 1 of the 3 desks - the others belonged to the engineer, who would be at the warehouse more frequently, and the sales manager, who was out making sales. It might be under-utilized, but both engineering and sales still needed their own desk, file storage, etc. for the times that they were in the office.
Real estate transaction costs can be huge, IF the rent is reasonable (apparently not this case) then paying rent on underused space is basically a real estate options market. There is a viable business model here, its like insurance that if you need an additional long term office next Monday, just walk in to "your" space. It might be cheaper to make one transaction, pay your 6% or more of commissions and fees, underuse the space, than to pay two 6% commissions and fees (and labor to do the second deal).
Several employers ago I got to learn about financial industry disaster recovery plans and you'd be surprised how many traders have an empty office squirreled away on the other side of the city as their tornado/fire recovery plan. Sure only 1/20th the employees would fit, but its only 5% the rental cost of the real office and some bean counter said that was an acceptable loss to provision an office with no people and a stack of server hardware. If they let people work from the D.R. site that would be a public admission that people don't need to work in a bullpen and could just as well work from starbucks or home, but that would not meet the emotional need to intimidate people in person and demonstrate butts-in-seats metric goals so using the D.R. space for actual work would be unthinkable unless the main office was literally on fire.
This combines with open office style, such that people can't avoid noticing unused space, although unused space is hardly a new feature of the business world. There's a small room right down the hall from me, but its behind a locked door, so no one notices. If they were not an open office company, they'd just lock a door and no one would notice. Placing their capacity on display like this is arguably an architectural design fail, they should have found an architectural way to "hide" empty space from casual visitors in an attractive and cheap manner.
One of the many signs that things are getting toppy is that everyone stops working. Or rather, they "work from home". It wouldn't surprise me if many of these tenants are underutilizing their space because most of the people who were supposed to fill it are out somewhere else goofing off, sleeping, etc. There's no need to worry about being productive when (a) your employer can't readily hire a replacement for you and (b) there are 50 other possible employers who would fall all over themselves to give you a job (and a raise!) regardless of your competence or diligence. Besides, who cares if you're leasing twice the space you need for a bunch of employees who don't come to the office and do no work? It's not like you can't just raise another huge round whenever you want.
Other private offices appear to be entirely unutilized (i.e. they're occupied but I never see anybody in them). The latter seems to be more common with large companies that have "real" offices elsewhere and don't really need space at WeWork.
Obviously, this is entirely anecdotal.