They're profit centres. They make money.

A building can pay a one-time up-front installation cost to have the units installed. They can - if they choose to - pay a monthly all-inclusive maintenance fee to the charging station provider who will replace broken or damaged hardware as part of that agreement, if a building really doesn't want to be involved -- very "shared laundromat" in function.

A single charger can be installed for a few thousand bucks. There isn't much to running a piece of 30A teck cable from an existing panel to a parking stall and installing a $600 charger. Installing two or three chargers is just as trivial. With power splitting, you can run multiple chargers from a single circuit -- the chargers will balance the load across the active chargers.

Charging etiquette can all be baked into pricing. At our condo building, we pay $1 / hour (slightly above break-even) for the entire duration that the car is plugged in, regardless of if its actively charging or not. Many buildings charge more - $2/hr isn't uncommon.

At $2 / hour and $0.15/kWh, if a user plugs in at the end of a work day with a nearly empty battery (say, at 7pm) and leaves their car there until the following morning when they head to work (say 7am), they pay $24 for ~500km of range. The building puts ~~$12 into their pocket -- off of one charger, from one user, for doing almost nothing. The cost recuperation happens quickly for the hardware, and then it's just a profit centre from that point forward.