If you are not established enough to take a 5 year lease, then wework (and their competitors, of which there are many) make a lot of financial sense, especially for the flexibility — e.g. if you downsize, rent goes down accordingly in 1 month. No “cheap” lease has this feature.
Also, WeWork is cheap compared to prices Regus used to charge 5 years ago; I would assume Regus did respond to the price pressure, but I haven’t checked.