I feel like the actual moral of the story should be "don't underestimate how trying to scrimp on a vital resource can result in horrible logistical complexities and a nightmare UX".
All true, but I would add that "in order to get back to the previous system that actually worked, you may have to provide a fig leaf for management, so that they can pretend no such thing is happening." We are back to one toilet per car, but we have to use cars of twice the size (with superfluous coupling in the middle that is never uncoupled) in order to pretend that we did not go back to the original system.